I haven't listened to the gr07 in a long long time! All I can definitely tell you right now is that the 750i is a much fuller 3-Dish sound over the gr07 (great sound but 2-D). There is more bass in the 750i, and I think quite a bit more clarity (but I would have to listen to the gr07 to be certain of that). Build quality definitely surpasses the gr07. The gr07 is a great phone however, and still has some of the best sounding drums I've ever heard in an iem.