The E-80 has a couple features that the G70 does not..features I do not need[text and BMP screens..not to be confused with lyrics read from SMF's]..
They have the same sound engines, and can read data from each other..

The E-80 has speakers, and considered more of a home unit..

The G70 has a better key bed, and 76 keys compared to the E-80.

Another important feature on the G70 are separate outputs..not available on the E-80..

For me ..the G70 is the easy choice..and I consider the G70 more designed and built for "pro" use..

If you do not need a mic input and harmonizer..Roland has the 76 key mid price E-60..with decent key feel[similar to E-80]..

My vote is for the used $2,000 G70..

Great board..right price...

Make sure you update the OS to 3.0..