Best Platter Material

With different turntable platters being used out there, is there one that is better over amother for vinyl playback?

The most common materials I've come across include:
- aluminum
- acrylic
- glass
- delrin
- ceramic
- copper

Also, if using some sort of platter mat (felt, rubber, cork, etc.) does it even matter which material is being used for the platter?
Yes. it does matter what the platter material is even if you use a mat and no, there is not one material that will guarantee the best sound. There are three very important things in audio; they are EXECUTION, EXECUTION, EXECUTION.
I've been experimenting with this for several years. It's incredibly complicated to answer as it depends on the turntable design, turntable platter material as well as the mat material.

My new found, favorite mat is the TTM from Japan, nearly 7 pounds of stainless steel and matched to same brand "oil filled" record weight. This works the best I've heard on my Technics MK3 but could be too heavy for a lot of tables.

A great second place mat is a toss up between Micro Seiki Cu180 and Cu500, both are lighter weight than TTM and softer material, less dynamic and overall warmer but also less money and easier on the turntable drive system and bearing (especially the Cu-180).

If those suggestions are still too heavy and / or too expensive, the Boston Carbon Fiber mat is a great option. Less money, available currently (others mentioned are no longer made) and light enough to cause few problems on most high end tables.

Some drive systems will be adversely effected by super heavy mats, so as soon as I (or someone else) suggests a mat, trying it for yourself may result in different outcome due to drive system interaction.

We have not even touched on the effect this extra weight might have on the suspension system (assuming the table has one). The mat gets the blame because it's the new variable when it might be you're screwed the isolation.

Just a few ideas about why it's complicated and requires some testing. Perhaps Stanwal's response "EXECUTION" is the simple answer.
I'm a Delrin fan. It's all about the implementation... damping, mass considerations of the turntable in question.
I go sandwich . stainless steel and Aluminium Alloy.
that should creat a platter .

In the 'old days' when TT was the only game in town, Dual had a 2-piece platter, either half would ring like a bell when struck, but together were nearly inert. Resonant frequency of each piece was carefully chosen.

For a budget job it was very good and well executed.

If I were building a 100% cost no-object TT, I'd investigate Carbon. I don't know if some of the more exotic forms...Graphene or Buckeyballs are available in large enough quantities yet. It may obviate the need for anti-static measures.
I like my Rega glass platter with a (thick) rubber band around the circumference.
The stock felt mat.
Boston Audio graphite mat works really well with Nottingham Spacedeck. Its platter is made of..I have no idea, but it's quite heavy and not glass or acrylic or delrin. Some sort of alloy.
I think the alumimum/lead sandwich of the VPI TNT made an excellent platter, but the platter interface with the record is a different story. for that I use and recommend Delrin, which is also my second place choice for the entire platter.
You are asking for two different things. One, which material makes the best platter and two, which material interfaces best with the record. The answer to those questions are likely two different materials, as I stated above.
Living voice mystic mat is very good.

Does all the things that my copper top on the TW Raven AC-3 does except removes the slight edge that can afflict the copper top.
The Kenwood L07D comes with a 5-lb stainless steel mat, a la the one Albert describes. I am a big fan of my L07D with this mat. I also like the SAEC SS300; like the M-S mats, it's no longer made but usually can be found on Audiogon or eBay for sale. Boston Audio Mat1 and Mat2 would be in my top 3. So, interestingly to me, Albert and I are in nearly complete agreement. (If I ever audition an M-S mat, I am sure I would like that too.)

As far as the stock rubber mats typically supplied even with the best vintage turntables, I feel about them the way Joan Crawford felt about wire clothes hangers (if you remember the scene from "Mommy Dearest").

But I thought the OP wanted to talk about platters, not platter mats. To that I would say that if you use one of the above mats, the composition of the platter per se becomes much less relevant.
The variables and combinations can get complex, as a change in weight may also affect speed stability. I like the old VPI TNT delrin/lead/cork platter, topped with a 4 lb. TTWeights copper platter, topped with a Trans-Fi Reso-mat, clamped lightly with a 5 lb. brass clamp. The Reso-mat elevates the LP on small vinyl acetate cones, reportedly of the same composition as LP vinyl. The original platter is a bit over-warm and lacking in detail. The additions add clarity.

Similar process to baking a cake.
The best platter pad I have ever seen was made by Warren Gehl, who is currently working at Audio Research. His platter pads are now pushing 20 years old but are still getting good resale prices when they show up.

The issue here is the durameter (hardness) of the LP vs that of the platter pad. Too hard = bright, too soft = no bass in a nutshell. When the two are the same hardness, the pad is able to absorb vibration from the LP. Now this is important- put an LP on and turn down the volume. The better the pad, the less you will hear coming off of the surface of the LP itself. If you think that is not talking back to the stylus you would be quite mistaken!

Once the pad has absorbed this vibration, it cannot reflect it back to the LP. On top of that, the stylus exerts considerable pressure on the LP surface! 1.5 grams may not seem like much, but given the size of the needle its like several hundred pounds per square inch! The result is that the LP depresses slightly within the immediate vicinity of the stylus. The platter pad must support this and not also depress.

Finally, its good if the pad also provides some damping to the platter, without that function interfering with its ability to damp the LP.

Most pads are too hard- any metal, acrylic, glass and the like. Of the list above, delrin is the closest. IMO its unfortunate that Warren no longer makes his pad. When he did, what we found was that as long as the 'table could manage the weight, that table would sound instantly better (better bass, smoother more detailed highs) than any table without it.

I've been thinking that the thing to do is to build a pad out of a blank LP, bonded to a damping product that has a metal substrate, perhaps stainless or aluminum. This would have the correct hardness, being the same material, and the damping control at the same time...
Ive always wondered why people didnt just use an old record as a mat, if the intent is to match the impedence of vinyl. Nothing could be closer than another record, and there are certainly plenty of mitch miller or lawrence welk albums out there to make as many mats as the world could use. Maybe sand off the grooves so it is perfectly flat and then bond to the platter.
You would think that Harry would have settled the matter, after 30 years. Harry keeps changing VPI materials, but that is only because of the need to keep selling stuff. I am sure he figured it out years ago but would never admit so. Years ago Harry adopted the automobile marketing model, which is repackage every year or so. Keep the money flowing. So, lets ask Harry to come clean!
M Fremer in his last article about the VPI CLASSIC 3 turntable (best analog component of the year) wrote aluminium is the best material.

One point for acrylic, check the best turntables in the world (Transrotor, Clearaudio...) all of their flagship models has this platter material
I think you are right. To me these things are often purely dictated by whatever is the "latest fashion trend" in audio. When the HW-19 first came out it had an aluminium platter. At the time the hype about acrylic as a 'wonder' material was gaining momentum so the acrylic platter came out which received great reviews in TAS vs the aluminium one.
Then from vpi we had all sorts of combinations of acrylic/lead/stainless steel/delrin/aluminium etc and now surprise,surprise 'wow' the aluminium platter is back in the classic.
So I think the earlier poster who said execution is paramount was right. Imho all sorts of materials can be made to work well in the appropriate design.
I've read that Clearaudio is switching from acrylic to POM (delrin) with a ss substrate.
So, instead of ascribing some nefarious motive to VPI and others, why isnt this just a case of a manufacturer trying things to see what works best and a certain price level. It is much easier to machine or cast an acrylic platter than a 2" thick aluminum one. And I'm sure VPI's multi laminate lead platter was expensive to manufacture. Transrotor uses mainly aluminum on their better tables. Look at Teres, they went from acrylic to wood to delrin. Was that just to sell more, or was it an attempt to see what works better, for most people, most of the time, on most systems.
I dont have a turntable with an acrylic platter, but they looked nice and shiny at the time they were in vogue, brought on mostly by the Clearaudio Statement, and the theory of matched impedence seemed reasonable. Now we have moved on.
Not everything is a conspiracy by business to screw you.
12-08-11: Brf
I've read that Clearaudio is switching from acrylic to POM (delrin) with a ss substrate.

They have been Delrin now for quite some time with their upper tier tables (Innovation series), along with the Concept and Ovation models.
Stanwal is absolutely right. I would never have thought, for instance, that a solid state phono preamp could satisfy me. Tube are better than SS. That's until I heard an ASR Basis. Now tubes be damned (sort of). It's all execution. And also execution. And he's especially right about the third thing.
Lead makes a good platter. Walker and Maplenoll utilizes the mass and non resonant qualities to great success.