Upgrading the stock cartridge on Macintosh’s MT5 turntable

Running the risk to get some flak saying that this arm-cartridge resonance it for many applications somewhat overstated...
It took me some time to come to this conclusion. 
My best guess though would be that your tt's arm, being only some 7 odd years old, would be off medium effective mass, somewhere between 10—12 gram effective mass, as most more current tonearms would be. 
Given that assumption to be quite correct, any cartridge with a compliance ranging from about 15 to 20 cu (compliance units) would be pretty well suited as an replacement.
In the price range of around $ 500 — $ 1500, replacing your current item, in my estimate, practically all new stock cartridges will be in this range.
So now the more important issue I'd see is whether you go for an MC or MM cartridge. 

What I perceive in your situation, as you have eluded to, I'd HIGHLY recommend a good MM cartridge - though NOT necessarily an item such as an Ortofon 2M Black.... as yet. 
It's a top performer but maybe a bit to tricky and can sound somewhat to bright in a number of situation. 
Audio Technica has a large range of current ones to choose from, Ortofon, Nagaoka etc.
All this is no rocket science. 
The issue with numerous NOS (new old stock) cartridges is that they quite often, in my experience, proof more tricky to set up, as well the tendency having been designed in the majority for more light-effective-mass tonearms i.e. of compliances 20 cu and some easily as high as 40 cu. (soft as butter in the sun ☀)
Depending on your setup, those could work fine too, I have some, but again not what I'd recommend. At all. 
I hope this will give you some more ideas. 😉
M. 🇿🇦 

M,

Thank you.  My current cartridge is an MC.  If I switched to a MM, would I have to change anything else?
current situation:

high output MC cartridge 
moving magnet inputs
Dural-Aluminum tonearm
2 grams of tracking force
6.3 grams of total mass
signal to noise ratio 36db-41db
Mcintosh states that impedance is 1,000 Sumiko specifies 47,000 for their cartridge.  Not sure why the difference?

Any *good* MM cartridge will out class most high output MCs, with no exceptions I’m off hand aware of.
Since their output voltages are quite similar, with the usual more minor variations, their loading at 47 kilo ohm (std. MM Loading) will also be the same.
There are, as always, variables on this subject as in most any analogue cases but this is where it’s at.
The variables might be such as higher loading preferred like 100 k ohm, different capacitance settings, and e.g. MMs with aircores having lower impedance and therefor a far lower output, those being in need of more than the quasy standard of 40 dB gain setting. None of what was suggested here.

So I’d say give it a go, and let us know how it went.
Michélle 🇿🇦

thank you 

You can certainly do better than the Blue Point. That tonearm was designed for cartridges with a compliance around 15. The Blue Point is 15. The Ortofon MM cartridges are around 20 which is too high for that arm.  The Clearaudio cartridges are 15-16 and will match perfectly. The Maestro V2 is an excellent MM cartridge. As far as tracking is concerned it will run circles around the Blue point. 
Grado cartridges will also work very well and are generally a bit warmer than Clearaudio designs. 
You can use low compliance cartridges by just adding weight to the head shell but these are generally low output moving coils and you would have to add a step up transformer.