The G1000 does not have the newer samples that the 2100 has. It does not have the terrific Yamaha mixer/effexts section and mic input. No speakers.....much larger and heavier .... the differences are huge.
They are both very good in certain areas, but they are apples and oranges in most.

As a stay at home controller ... the G1000 works just great, but I could never use on on stage in my situations - pro or not. I need more at my fingertips, that's all.