Well, I've owned and enjoyed the sm3 v1 for over a year, now. You can find my latest posts about the sm3 v1 around page 50 or so. I can no longer hear from the left earpiece, and have lost my original invoice, so I likely won't be able to get it repaired. Here is what I have to say about them.
The sm3v1 had a very warm, laid back sound signature. Too much so for my liking. Originally, I kept finding myself annoyed by how much the bass was interfering with the presence of vocals. Now, keep in mind, 95% of the music I enjoy is vocal. I know how my favorite artists' natural voices sound, and the sm3v1 colored them with a thickness, a throatiness for lack of a better term. It made the vocal sound more expansive, which is not what I want. I want bass sounds such as drums to sound expansive, not vocals or guitars.
Now, I know people were having the impression that the sm3v1's treble is toned down. I think while that is somewhat true, it's partly owed to the fact that these iems were very warm, almost dark. I remember when I EQed down the bass, I could hear treble in just the right amount. One thing I found very interesting: either the re0 (which broke before I bought the sm3) had great sibilance control (which is surprising considering their brightness), or the sm3v1 had little to no sibilance control. One thing that bugged me was hearing pronounced "sss" sounds. Sometimes, it got quite piercing when played at moderately high volume. I kept finding myself EQing the sound to get the frequency spectrum to be somewhere between the overly bright RE0 and the sm3v1... the sweet spot, so to speak. I didn't want to obsess with EQing, so I just stopped and learned to get used to the sm3v1's sound. I think my ears also eventually got accustomed to the sibilance. That doesn't mean I've come to embrace it, though. I like the sm3v1, don't get me wrong. I just don't love it, or even like it a lot.
I sm3v1 added to my knowledge of sound signature, for which I don't regret spending the $300 on them. However, now that my sm3v1's are broken, I'm finding myself revisiting head-fi and my interests are directed towards Westone 4, ATH-CK10, and Westone ES5.