This review will be broken down into two parts:
Part I:
When the SM3 arrived, I was pretty excited to hear what the fuss is about. I played my usual reference tracks through the SM3 with a silicone tip but what I heard disgusted me. First of all, it reminds me of the sound of the HD650 with the black silk baffles drivers: overly smooth, veiling sounding, a very thick lower midrange, recessed treble. And even with the veil, the details are there from top to bottom although the bass lacks the punch that I'm looking for.
The veil of the SM3 makes it very hard to listen into the ambiance and decays of a live recording. It's borderline stuffy sounding. Moreover, the vocals are so in-your-face that any spacious feelings created by the wider than usual soundstage (but not enveloping) are gone. Due to its overly in-your-face vocals, many tracks that pan vocals slight left or right lost or lessen that effect considerably.
Overall, the SM3 sounded very dull and I hated the it.
Part 2:
I was baffled as to why there are so many positive praises of the SM3. So I decided to give it a second chance by switching the tips from silicone to the Shure olives and I'm sure glad I did. The SM3 improved tremendously. The sound improved so much that the SM3 did not sound anything like the HD650 anymore. The treble is a lot more present. Along with the improved treble, the lower midrange bump is still there but has improved considerably hence alleviating most of the stuffy-ness and brought out more ambiance but the SM3 still lacks the palpable presence that I crave.
Decays of the SM3 are still short of what I'm used to. The overly in-your-face vocals with the silicone tips are now replaced by a pleasantly smooth but slightly forward midrange. Instrument separation has also improved because the soundstage is now a lot more spacious since vocals aren't as forward as before. However, I still feel that the soundstage is a bit too flat, lacking height and depth. I still wish the SM3 has more bass punch and crispness to its sound.
Overall, my impression of the SM3 changed tremendously from unlistenable to an enjoyable experience.