i do not play a G70, but i do play the E60, which in many ways is pretty similar. the roland's styles are the most reliable, IMO, they cover alot of styles, and they do it good!
roland has it's share of bugs or shortcomings, but glitches in styles? i cound not find that one!
OTOH, korg still has some problems with the timing when pressing fillins. i know because i have tested it, including pa2x. and the biggest "guilt" for yamaha is the styles are over quantized, they sound too mechanic and not "live" like.
you really should find a G70 and play it. it is totally different from s900, build wise, weight, touch, everything. too bad s900's build quality is not as roland's!....