Depends whether you want a 76 or a 61.

E80 has some more sounds (but fewer legacy sounds), .bmp viewer (Roland posted that there WAS a hardware reason no .BMP viewer for G70 quite a while ago), some OS improvements (fixed velocity for sampled organ tones, floating split point, etc.), more effects - 3 insert effects to G70's 1 or 2, 2 mastering EQ's and comps (1 for styles and smf's, one for keyboard), 2 SRX slots to G70's one, speakers and weighs more

G70 has the best 76 action on the planet (IMO), individual outputs, and independent output for the harmonizer/mike section.

For me, at least, the piano sound is SO good it cries out for a bigger than 61 keyboard, but if you don't play piano, don't need additional outs and don't want to run your mike/harmonizer separately from the arranger's main mix, you're probably more future-proofed with the E80...