SOTA NOVA, HR-X VPI, Technics 1200G recommendations?

It seems to me we are all coming around to the same place. 

@lewm, I handily agree that if things like contacts and stiffness are going to be a problem the are certainly going to be worse with a stiff, low output moving coil cartridge. This says nothing about record and stylus wear. 
I myself have migrated away from stiff low output cartridges and am using more compliant MM and MI cartridges. I also have to admit that many of my concerns are academic and I really do not know how much they affect the experience with the exception that lighter setups do outperform heavier setups. the oscilloscope traces I saw were more than convincing.
A tonearm with a detachable head shell may sound exactly the same as a tonearm of similar effective mass, without a removable head shell and with the same cartridge of appropriate compliance. As you say the most important issue is that the cartridge match the tonearm. I also agree that the differences between excellent cartridges is nuanced, not dramatic at all. Which makes me wonder why someone would pay $16,000 for a cartridge? Then again why would someone pay $250,000 for an amp?
Crazy hobby.

If it was my choice between the listed turntables, I would send the Sota back to the factory to be checked and upgraded.  That is an outstanding turntable.  

Second would be upgrading the arm to possibly a SME IV or V.

But, for the price range listed, I would keep the SOTA and upgrade it via the factory.

enjoy

What is the advantage of using a low compliance cartridge? Is it for a specific sound character? Otherwise it seems like one is limiting himself to heavy tonearms.

All cartridges are:

-Hight compliance
-Mid compliance
-Low compliance

1) Most of the LOMC are low or mid compliance (very few MC are high compliance like Ortofon MC2000 for example)

*A low compliance cartridges must be used with superheavy tonearms.

2) Most of the MM/MI are mid compliance or high compliance (very few are low compliance like Nagaoka for example).

*A high compliance cartridges (in theory) must be used with very lightweight tonearms.

There are limits in every category of cartridges, and using a mid compliance on mid mass tonearms is not always the best solution. A compliance alone will tell you nothing about sonic characteristics of a certain cartridge. It can be a perfect tracker (high compliance), but boring as hell. A low compliance MC also can be boring.