Great find on the XP60 for $850! They usually sell for over $1000 used, though I've noticed prices on the 60 and 80 have been falling on eBay lately, perhaps because of the emergence of the Korg Triton and, now, the Roland XV line (though none are workstations). I sold an XP50 with a stand recently for $650, so you did very well with your XP50 as well!
I bought an XP50 as an inexpensive way to obtain the expansion boards it contained (to use in my XP80). I didn't notice anything poorly constructed on it or anything, though. I think it is a great synth for someone who cannot afford to get a higher priced workstation. I can say, though, that after you use the XP60/80 for detailed sequencing and sound programming, it is definitely difficult to scroll through all of those pages on the 2-line LCD and make all of those extra button pushes on the 50 (or 30), despite already being familiar with its "architecture".
As for the "grunge" phenomenon, I feel the same way as you.
Why are you "totally happy that you did not get a Korg"? Which Korg workstations did you consider?