Pros: Soundstage, deep bass, lush mids, smooth highs, comfort
Cons: hmmm...they are IEMs and not HD650's? Stock tips are just WRONG.
What's not to love about these? Ok ok...they're French. Fine.
There's not a whole lot I can add to what has come before, but...
These very much remind me of my HD650's, minus the openness of presentation. I don't find them muddy or congested, just a tad on the warmer/darker side of things, which I love. Ample and suprisingly visceral bass isn't something I was expecting from a 3xBA, but it's there in spades. Midrange to my ears is slightly accentuated but in a pleasing way. Highs are clean and slightly rolled off. Lovers of Sennheiser's house sound should love these. AKG fans, not so much. These are the polar opposites of my Ety ER4's...very fun, lively, lush and warm...not dry, sterile, analytical and boring. They are also not the miserably uncomfortable ear-spears that the Etys are either...I can wear these for hours, and even sleep with them in.
Also, regarding the "short cord" complaints...you guys DO know they are meant to be worn over the ears, with the cord behind your head, right? Slide the clear thingie up to tighten the fit to the back of the head, and you'll have a cord and fit that is totally unobtrusive and extremely comfortable.
Gripes? Well...I don't think the mids and highs benefit from a touch of EQ in order to balance them out a bit. Tone down the mids, add a little top end, and all those complaints of "too muddy, too bloaty" go away. Also, the stock bi-flange tips are ok and the Comply's are very comfy but they really wreck the sound on these. I think the users griping about muddy/bloaty/congested/blahblahblah are probably using the Complys. See below...
It took me a while to find a good pair that was a trade-off between fit, comfort, sound quality, and isolation, but once I DID, it really changed the overall SM3 sound to perfect without EQing at all. I'm using some MEElec M6 tri-flanges. These are soft silicone with a larger diameter inner tube/sound chamber, so you need adaptors (either make your own, or in my case I use the little red Monster ones). The larger space in the tips makes for a more open soundstage, and the material doesn't muddy up the lows and mids and absorb the highs like the foams do. Only drawback is they are a little thinner in construction, so they don't isolate extremely well (they DO isolate just fine, but with no music playing it's not like Etys in that you can hear people talking to you...you don't have to lip read). This is fine as they are easily the most comfortable tri-flanges I've used. For reference, I tried several different Comply models, all of the Monster Super Tips (foam and gel), Ety tri-flange, grey and yellow foams, Sony Silicone, Shure Olives, and of course the stock tips. All I can say is reserve final judgement on these IEMs until you've tried a lot of tips, and you WILL be rewarded once you find what works for you.