im still using my SA6. definitely love them with my klipsch image tips (more deeper bass, lose a little in soundstage). the sound is great. using treble+ and new bass + port, the sound is clear and lovely. the treble is at a place that doesnt fatigue my ears except for those few badly made songs with extremely un-necessary cymbals/rings. bass is tight and deep. mids is excellent, especially vocals. probably the weirdest thing with these is the drums, sometimes they sound too dry and many find them to be unrealistic. like some have said before about the SA6, they are like a slightly warmer ety. extremely great with instrumental and vocals, however with more "fun" music (rock and hiphop), it feels as if the extreme clarity and cleanliness of the SA6 sound sort of kills the fun magic in those genres.
as for build quality, i did have a couple of issues before i got my perfect pair
. jason and bill were extremely great people to work with. sleek audio's customer service is just amazing (CALL, DON'T EMAIL!). the biggest problem with them now is that they are just so swamp with orders, especially customs, that they just can't do everything perfectly. from what i hear, jason gets hundreds of emails and there is no possible way for him to answer them all as well as work with the customs and etc.
to be honest, one thing to keep in mind is that these are IEMs. no matter how great IEMs get, they are still IEMs and the difference in quality of sound is just a lower ranked class than headphones. i honestly can say that after listening to my ATH-ESW9 (unamped, straight from itouch 2nd gen), the SA6 has no match against headphones. the most noticable was the bass not being as well defined compared to esw9. i believe that IEMs, especially BAs can only do so much and considering that a single BA design is producing sound quality that this clear and precise level is already amazing.
btw, i believe that right now IEMs is going through a big phases. before there were a lot of talk about triple.fi and se510. then it went to sa6 and couple others. then there was the soundmagic pl30 which received a lot of hype. following that was the releast of westone 3 and ie8. after that was the nuforce ne-7m. now we are at the phase of phonaks. all i have to say to this is.....wow guys....