So I guess I'll make this a short comparison instead of just ranting about how much I love them. This is for the GR07 MKII vs. the Shure SE215 (I know it's not the same price point, but still... it's the only comparison I can make since those are the only quality IEMs I've previously owned). Excuse the untrained language, I'm new to this. Just bear with me
BASS:
The bass on the GR07 is less "loud". I mean, I can hear it a bit less. However, I can feel it a lot more. I don't really know if it makes much sense, but I feel the bass "hit" me when the drummers hit the bass drum, or when a bassist plucks a deep note. I'm not sure if I like this more than in the SE215s, but I definitely like it.
MIDS:
This is a part I really love about the GR07. Vocals sound much more realistic and guitars sound so much richer. I swear, I got goosebumps when hearing some acoustic songs. I almost shed a tear or two listening to Opeth's Damnation, the sense of... reality is just amazing.
TREBLE:
I don't know if it's because I come from an IEM that is known for it's relative lack of treble clarity/detail/awesomeness, but the GR07s sound so amazing in this area it's hard to describe. Guitar solos, cymbals, violins... they all sound very present. I haven't tried them with high female voices yet... will probably update when I do.
COMFORT:
They basically disappear when you have them on. I guess there's not much else that needs to be said.
Overall I find them to be pretty amazing. I wish they had a BIT more bass, but I can't really complain. Especially with the quality of the sound I'm getting, as well as how detailed I find them to be over the whole spectrum. Not disappointed in any aspect, would recommend them to anyone looking for IEMs in the $200-$250 range.
P.S.:
I also received the GR04 Pro (for free, no less) and let me tell you, for the price they are AMAZING IEMs. They've got really nice bass and mids, even though they sound kind of veiled. I'm really happy with my purchase, no regrets at all.