SME V tonearm versus Rega tonearms on Michell Orbe

Does anyone have experience comparing the SME V tonearm on a Michell Orbe turntable with a Rega arm, either a stock Rega RB 900, RB 600, RB 300 or RB 250, or a modified Rega arm (e.g. Origin Live RB250)? I am interested in using either a Benz Micro Ruby 2 or Koetsu Urushi as the cartridge. If you can give advice regarding sound or set up capabilities, that would be most appreciated.

The Rega is no match for an SME. Rega tonearms are entry level. SME is the real thing. Just my.02.
Hmmm, you are contemplating putting a multi-thousand $ cartridge on an arm that costs a few hundred $? Doing just the opposite makes far more sense. If you are looking to stay with UK arms, the Naim ARO may very well be your best choice....otherwise the Graham 2.2 or Triplanar are the way to go. I found the SME to be too much in the bass and lower mids when I was comparing arms a few years back...and this was on a VPI TNT.
I use an OL RB250 on a Gyro II SE with a Benz Ruby 2 cartridge and the sound is the best I have heard (compared to any other TT system I have used). There is an unmistakable synergy going on with this combo that is captivating. It easily outperforms my former VPI Aries with JMW 10 arm, flywheel, PLC, and ClearAudio Gamma cartridge. I would expect properly set up Regas to work great on the Orbe as well, but I can't say that it would beat an SME V. It is doubtful, but I haven't made the comparison and you never really know how well a certain combination will perform until you try it and hear it in your own familiar system. My Michell/Rega/Benz sounds scary-good -- of that I am confident. Good Luck! :)
Koetsu cartridges work phenomenally well with the SME 5 tonearm, but I have only tried the combo on two SOTA turntables and then on an SME 20 table, which I am presently using. There certainly was no extra bass on any of those, but I don't know the table you have in mind. I can't imagine using a Koetsu cartridge with a Rega arm--a no-compromise cartridge with a good bang for the buck arm sounds like a waste of cartrige dollars.
Believe it or not that's it's OK to compare these arms. I believe that analogue setup starts from CARTRIDGE first and ends with phono.
The downsides of Rega arms are tonarm and phono wires, somewhat suspension and counterweight. By modifying cheep Rega arms with Origin Live or Incognito, you will rich an increadible level of performance that is THE match to SME arms(just much less $$).
After Ingognito mods in my RB300 I've realized that I had to do it along with buying my GyroDec.
I think the limiting factor on the OL Rega arms has more to do with the relatively inconvenient, time consuming methods of setting the VTA, rather than the actual performance difference between it and the high-priced arms. If you get an OL RB 250 dialed in correctly to the cartridge I think it comes surprisingly close to the performance of high-priced arms (perhaps too close for the comfort of some expensive-arm owners). Hey, if I plunked down 2G's or more for a great arm, I wouldn't want to believe that a $500 arm could sound nearly as good either... :) But if and when I do move to a more expensive arm, it will be mainly because I want a faster way to set VTA.
You might want to explore the SME if you are using an MC cartridge. The was made to work with MC's and is suggested by Sumiko. If you get the VTA option and the breakout box, it is essentially the same price as the SME V. I frequently listen on an Orbe with the and they are a very nice compliment to each other. Stepping down to the Rega makes little sense for the caliber of table and cartridge you are talking about.
I've just bought the Orbe SE + SME V + Benz M2 about 6 months ago. I had contemplated about the OL RB 250 as the option. For the price, the OL RB250 is hard to beat. Don't bother with the original RB250 arm, the OL mod is worth the additional few hundre bucks! However, the Michell tables were designed using the SME V arm. The SME V have more synergy with the Orbe than the Rega arms. I think the SME was SLIGHTLY bettered than the OL Rega in terms of fuller sound, wider soundstage, and more bass. (stress on slightly) But the OL RB250 comes very close to the SME V for a fraction of the price. It's that high-end thing, you pay $$$ for that extra 5-10% increase in performance. Is it worth the money? You will have to decide. I could not pay $3200 for an SME arm, so I had settled for an OL RB250. But while I was in Hong Kong earlier this year, I found the SME V from an authorized dealer was only selling for $1800. That was cheap enough for me to abandon the OL RB250 idea, and went for the SME V.

If you decide to get the OL RB250, it might be cheaper to get the arm directly from Origin Live from England. It would be cheaper than buying the arm here and sending it to OL in UK to get modified in most cases. Make sure you get the whole mod package. Like what others said earlier, adjusting VTA would be a pain in the butt on the RB arms. Good luck!
Thanks for all of your responses. I am inclined toward the SME V because it has adjustable damping with the silicone trough and the arm itself is lined with a damping material. I have convinced myself that a touch less brightness in my system will suit me and a bit of added bass and lower mid warmth won't hurt - I can always work that out (make the sound leaner) with tube selection and put a little "edge" back in the tonal mix.

The SME V also offers really good set up tools and methods for fine adjustment that the Regas do somewhat poorly. Taking the arm on and off to insert washers strikes me as a bit primitive. I also understand that the Rega arms are very sensitive to the pressure of the nut on the underside of the arm affixing the arm to the armboard. I do not want to fiddle with that too much. I also do not think that the Regas offer any real adjustment to azimuth, though the SME is not easy to adjust in this way.

No order placed, yet. Steer me right if you have additional thoughts!
The VTA and VTF with high-end cartridge needs precise setup to extract the best. The exactness makes the jump from good sound to magical transformation. OL or not, whether the RB250 is a good arm is meaningless when the cartridge cannot be set-up accurately.

It works fine if the cartridge body happens to match the physical geometry Rega had in mind. Similar problem with Aro, while it has VTA, it cannot adjust overhang.

I had 3 RB250 and all the mods, trying very hard, they are not in the league, just another Best Buy/Best Tweak. Not a world class arm.
Extremephono, you have just commited a sin! Blasphemy against an untouchable component in the high end audio circles...

The Rega arm is REFERENCE in reviews and, as such, epitomizes class, finesse and status.

Just my .02.
I forgot to add that the anti-skating on the RB250 could never be adjusted to spot-on accuracy. Forget about putting any worthy cartridge on this arm, as it will be ruined after couple hundred hours, the cantilever would have slanted to one side, for lack of compensation.

This can be fixed, I use a cotter pin to screw to the left cartridge mounting screw. Adjusting the span of the cotter pin and careful setup with HFNRR at least bring the anti-skate to within a workable range.

So, after you purchase the RB250, added the mod, don't forget, you'll need a cotter pin! (OK, this is a joke, not my URL..)
Rather than spend the extra $$ on an SME V, get an SME IV.6. I have one on an Orbe (using an old Spectral catridge) and I think the combination is sensational. There are a couple of options you can get with it which will bring it very close in functionality to the SME V, but will end up saving you about $1000.