The costs and/or difficulty in getting a 'stat rig are IMO overrated.
What I never liked was the voicing of the mid-level Stax (303, 404) but I haven't heard the new lineup. If it doesn't suffer from the same problems then it's even more reason to go 'stat. Then, there's always the ESP950.
Well... I don't think they're overrated... you have to be pretty patient, or lucky, to find what you're looking for at a good price - they just "don't grow on trees."
Do you just change out the plug on the ESP950 to use the Stax Pro jacks? Indeed that might be the best way to assess the stat sound, if you've already got a Stax amp (which I do).
And... I guess you got your MKI from "Osakaears" on Audiogon. I looked at those to, but opted to buy the MKII's on there at the same time - unfortunately, the MKII seller backed out of the deal at the 11th hour.