Here are my two cents worth for my findings with my IM70 >50hrs at least.
Bass: Slams hard and very physical, not overblown and does not obscure the mids.
Mids: Very nice, sounds correct to say the least
Treble: rough, it is not the strong point of this IEM to say the least. Lacks air.
Soundstage: Very closed sounding to me compared to say, a CK100
Detail: Not a particularly revealing IEM but clear sounding enough for me, greyish blackground that does not work well with piano recordings in a quiet room. Very forgiving IEM.
Since the bass and mids integrate well, they work well with to reproduce the electric guitars low notes and growl in Bad Horsie by Steve Vai. You would be hard pressed to find an IEM with such tactile bass(not overblown but with dynamics)
Nice impressions. I agree with you generally. I don't find the treble rough but I agree they're not this IEM's strong point. Totally agree about piano recordings. They somehow just don't seem to produce a very natural sound with piano. It gets a bit thick and muddy, not open and clear.
For me the soundstage is closed, in a way, which I think is caused by the thickness of the sound, but at the same time it's pretty wide, or large. I don't know if that makes sense.