I have exactly the same problem as The_Doc_Rock - guitar sounds thin, ugly after upgrade. I have brand new, Korean JTV-69 so this behavior is probably not specific for certain model/production batch.
Thank you..!!! I thought I was all on my own there for a while
Just kidding - seriously, there does seem to be some variation in the impressions of the v2.0 firmware in this forum, and even accounting for differences in taste and preference, I'd suggest that some of the less favourable impressions are due to real problems.
For sure, there is no way that the sounds coming from my JTV were usable with the update. And they sounded nothing at all like the video clips that a couple of folks have now put up.
In case anyone missed my earlier post, which has been bumped back two or three pages already, I do actually own a '62 L-series Strat (a real one), an ES-335, and an ES-175 (as well as a lot of others - but we won't get into my severe case of GAS...). So I do have some basis for comparison with the real thing. And v1.9 firmware, on my actual JTV, sounds VERY close to those guitars when switched to the models that are supposed to sound like them.
But the v2.0 firmware sounds NOTHING like the real things. (Not all, as has been discussed. The Lesters in particular are good)
We need to try and determine if we're looking at (1) a real problem here, and (2) what are the possibilities that could be causing the variation - why some have the problem and some don't. It needs a very logical approach and analysis. But I suspect that there MAY be a real problem for some - including me - and if anyone can think of possible causes then this may help Line6 in trying to sort it out.
The suggestion someone made earlier about possible flakey RAM, and the new update needing more RAM, is a good suggestion to start with.
Any other ideas?