Hey, I agree with you on the Session board. If it's any board you are gonna add to your setup, this is it. This is like the standard JV/XP Board to have.
However, the Bass & Drums is sure to keep your synth going for YEARS to come. I had the Roland Audio JV/XP CD Demo. I heard the Bass & Drums Demo on that disc and like you was not really impressed. It's not until I checked it out that it blew my socks off.
Check out patches like: "XPx30 - Acoustic Touch". That Acoustic Bass is too much on the side of having a real bass player. I've even fooled many bassists. They say "Who is that guy?". "XPx131 - DynoPiccoloSnare Kit" is good too". With the velocity split feature, you can get some convincing fills going on the snare.
Good luck man. The demo sucks, but when you check it out, you might just keep your XP/JV longer than you expected. Oh and BTW, get the Session board when you get a chance - No I don't work for Roland!. Good Luck.
The Infamous EPU.