I got the A5000 sampler today. It's the most absolute biggest pain to use. And whoever said it was thin... you were right, and I was flat wrong. It is thin. And this would a major pain to use everyday. It's huge and heavy and a real pain, and I can't see having fun with this pain in the butt. The SU700 was a little easier and actually taught me a couple things about sampling but Yamaha samplers aren';t for me. They say Yamaha effects are just so darn good. I disagree. They use the same effect engine in everything, just as they did way back with CS1X which was the most plastic sounding thing ever.
I majorly did not like this machine and the navigation is just weird and wrong.
Now I'm thinking about an Ultra.
I've got an A5K, and an Ultra too. The Yamaha UI is like most Yamaha UIs, which is to say, it could be improved. That said, I don't think it is bad. I can get around on it quite fast.
As it concerns the nature of the sound, it to some degree sounds like what you put in it (duh), but I think the filter character is quite forward and present in a way that is quite different from E-mu. I like them much better for electronic-sounding timbres.
I think the effects are quite excellent - they really respond when programmed. I value Yamaha's continual evolution of a set of algorithms.
That all said, I'm not disagreeing with your experience - it is what it is, and you're not wrong (for you). On the other hand, I do question anyone who decides something is not suitable (or is suitable) on the first day of use, especially with something as broad and deep as a Yamaha A5000.
The size of it is a PITA, and the disk routines just plain suck.
I do think there is a heck of a lot to recommend it, weak aspects considered too. I say the same as it concerns my E-mu Ultra6400 w/RFX + 2 ROMs.
cheers,
Ian