John,
I'm in the EXACT same boat!
I hate to give up all the features/editing/song book/touch screen etc etc on the PA...but I'm also thinking of a change.

I'm reevaluating the music I play and which arrranger is best for that purpose!...not necessarily the best in genral.

If I were you I would wait....something great is coming from Korg (don't know when, but soon) How about 4 fills? Lots of DNC sounds, some new styles..etc.
However...If availablity of styles in general is a real big issue for you (and me)...Yamaha will be tops.

But, As some said here...how many great styles do you need?

I would like some song specific styles...because I'm less talented than some...I can do my own, but I would rather just play.

The Korg does allow lots of changes/tweeking with a great editing tool onboard.

And with all the bugs they are finding on T4???

Lee S.