E60 is a little brother to E80, and that means less styles (with less complex structure), less poliphony, and more important, less sharped sampled sounds. it was a large discution at the time when the both boards were released about the clarity and quality of sounds, and i also got to the conclusion that even though the sounds are the same as number (i hope i remember right) the quality of the sample is pourer on E60. you can easily notice that also from the demos on their website.
nevertheless, the E60 provides you with some features that none other keyboard offers in this price range: 76 keys (with good feel), guitar mode (very handy in writing guitar tracks), good styles, modern and very inspiring, good sounds, etc.
i wouldn't call the styles "inferior" to E80, but just less complex. in fact, many of the E80 styles are also in the E60, but modified as structure, according with the hardware's possibilities.
as my oppinion, i would say if you really like E80 (many don't, so be noticed) you would not go wrong with E60 either. the best way, give them a try when you can.