I purchased the sleek sa6's about a year ago for around $200. forewarning: DO NOT buy these for $150 from z electria (amazon), they're fakes and sleek audio will not honor the warranty etc. on these. i haven't seen them anywhere for under $200. that out of the way, i've thoroughly enjoyed the sa6's. they've been my main travel/airplane/anytime earphones for the past year and i love their fit and sound signature. I'm not as well-versed as others on head-fi as I don't have that many earphones to compare, but I will say that these are the first earphones i've had (after trying at least 6 or 7 pairs) that fit like a glove. i've worn these on 5-6 hour plane flights and only took them out to hear what the pilot was saying, which usually led me to put them back in like 2 seconds later.
i tried the ue super.fi 3's right before i got these, and the fit was so horrible that I never used them. I have tiny ear canals and was on head-fi for a few weeks before deciding that these would be the best option for me. i was looking at the westone um2's, etymotic er-4p's, shure se530's and a few others. I went with the sa6's because i liked the idea of the customized sound signature (i use the bass+ and treble+ ports) and it really does deliver. the er-4p's sounded like they wouldn't have enough bass/oomph to them from what i read on head-fi and i went with the sleeks over the shure's for price, and over the um2's for the potential customized sound signature.
I listen to mainly modern rock, some punk, some metal, some hip-hop but i don't change up the ports to suit whatever i've been listening to at the time. i find that i like the signature for the music i listen to which doesn't vary too much. i've had these for a year, and i just checked the sleek-audio site, i guess I have the "old" sa6's. I've had no problems with build-quality. none of the ports have ever fallen off and i always just wrap these around my iphone and put them in my pocket. i live in the boston/cambridge area so i use public transportation a lot and i've never had any problems with the ports of earphones falling off or anything.
I originally thought the double-flanged eartips would not work well (as they haven't in the past) but i use the small double-flanged eartips with these and they stay in securely and are extremely comfortable for stock buds. the earphones practically disappear in your ear as they are pretty tiny. there are some good pictures here on head-fi that show you how tiny they are. i did have one of the eartips fall off when i shoved them in my pocket once, but i picked up a 5-pair pack of the same exact tips for like $15 from some company in canada.
i also like the fact that the cable pulls out of the earphones pretty easily. the cable only comes out when you deliberately pull them out of the buds though, so no problems there. I've used them on several occasions when i find myself at a random concert and right next to a speaker. they've come in handy for saving my ears for ringing for a few days. i've also done this on plane flights so that i don't have to be told to "turn off my iphone" when i just want to use these as earplugs. i just unplug the cable and there are no issues. i've slept through many a flight this way
i haven't gotten the w-1 wireless option yet (it came out after I bought the sa6's), but I will whenever I want to try it out. for now i like that i don't have to charge anything to listen to my music at length.
i'd search the head-fi forums for info on the other earphones you're considering, as this community has been the most invaluable resource for all my headphone/earphone purchases.