Here is my 2 cents short impression.
I just bought the SM64. This is one IEM that is every bit as good as fitear 334. I believe I have the revised version as the treble is not harsh yet it still sparkle (a very rare quality and not easy). TG334 is darker than sm64 and AKG3003i is brighter than sm64, so SM64 sit in the middle. It similar to EX1000 treble quality.
Base on memory the soundstage is slightly wider than fitear 334 but not as tall. Imaging is fantastic, really good..very 3D overall. Bass quality and quantity is really good. Bass is tight, goes deep yet not boomy (another rare quality), I can feel there is a sub woofer equivalent here with a very properly tune crossover and does not muddle with the mid. TG334 has more bass quantity (sometimes too much), but does not go as deep as SM64. The vocal sound very natural, again it sit in the middle between fitear 334 and AKG3003i, not too creamy, not too hash, just the right amount. I don't find it a V shape sound at all.
Fit is perfect, I am using the silicon tip similar to Shure 535. No vacuum suction feeling when pulling in and out of ear.
This is not burn in yet. I have only 10hrs now. Will keep burning in. I am using Centrance Dacport 1ohm mode. So far I really like what I hear. Isolation is as good as Shure 535 but have not really tested it on the plan (which I will next week). By the way it sound good even with my Samsung galaxy S3 hp out.
I don't quite like the plastic shell, I hope they use metal like the akg3003i or use some resin mold similar to TG334. When I first had the SM64 in my hands, I was turn off by the look, it looked like $100 to me, but when I put it on, I was like wow, I was blown away. I think the sound is worth close to $1,000 in almost the same league TG334 and AKG3003i which is pretty good, I can't seems to fault it. I sometimes do wish it is slightly more airy like what a really high end phone would have or al least on par with akg3003i or TH900, but it really is good enough, I don't miss anything here.
So in short SM64 look $100 with a $1,000 sound. Its really a fun audiophile IEM.
More impression coming. I will also be testing the IE800 and see where SM64 stands.. next week.