Go for that SC880 if you could find it. It's like a compilation of GS, JV/XP and SRJVXX sounds in one unit. The sounds (tones) are spectacular. It's a little less programmable than the JV/XP but the sounds are so good - much like having a JV2080 with a couple of expansion boards thrown in.
The choirs, strings, pianos, drum, EPs, et. rule. Go for it if you could find it. I got mine for $350 U.S. back in December. I also have an XP60 which is equivalent to the JV2080.
The JV2080 is more expandable and as you get more cash, you could expand the sound set from 640 sounds to over 2900 with the expansion boards. Note the falling price on the boards as Roland just issued their new XV line. The SC880 has 1,117 sounds built in.
I've seen the SC880 as cheap as $299 (It should really go for much more than that as this module is heavily underrated) and the JV2080 as cheap as $699-$750 here in N.Y.
Look hard. Good Luck
The Infamous EPU.