I'm not having any problems with the s950, in fact I'm very comfortable with it. I've pretty much upgraded from PSR1500 all the way up to the 950. They've all been pretty darn good machines. I started this arranger trek with an iX300 and have done very minor time with an i40m and the MicroArranger. I like most of the Korg features, and I feel they've improved their pianos. So, I'm just sitting here thinking if I'd like to give the PA900 a try. Ideally, I'd love to be able to sit down with one for a few hours or days and decide that way, but trying to find one around Detroit is difficult at best.
Additionally, I have the BK7m and a Hammond SK1-73 that I'd love to use, but having the 950 around makes it too easy to let things be and just pick it up and take it to the next job and the next and... A new board might force me to make some changes I've been too lazy to make. A new model, unless its a real earth-shaker, is just more money for features I really don't need or use. The 950 is holding its resale value right now, so this might be the best time to make a move.
I really should wait a month or so; this is not a good time for me, but my mind got to working on me, so I thought I'd throw the idea out there. That's my reasoning - no problems, just curious and a little bit fickle...