Okay, some short, first impressions ;)
Edited by Tom Yum Goong - 1/1/13 at 2:33pm
I use them with my Cowon J3. Volume seems to be a bit low (for the obvious reason) so I ordered an iBasso D-Zero to amp them.
Soundstage is just incredible! (Never had the chance to try the SM3, but I think its on the same level)
Bass is well textured, precise and has a good punch to it.
Mids are very nice too, but sometimes very distorted guitars sound slightly recessed, which is a bit irritating sometimes.
I really like the highs, but the TF10 (with its darker and not so neutral sound) made me a bit sensitive to them...they sound a little bit harsh sometimes, but this may just be my weaned (?) ears.
The transparency and the instrument seperation are amazing :) Sooo many details!
Overall they sound very natural and neutral to me (except for that dip in the upper mids).
As I mentioned before, I don't really have any other decent IEMs to compare them with (my beloved TF10 died a few weeks ago) and I received the SM64 like four or five days ago. So be a bit patient :)
I hope you can stand my not-so-proper english ;)