Pros: great bass and mids
Cons: less than ideal treble
Comparing a bunch of universal IEMs, I'd rate the Shure se535 as one of the top tier choices. There are a few issues, but how much these affect you will be dependent on each person's ears physically and audibly.
Basically, I find the shure 535 to be a very pleasant smooth sweet sounding IEM with the major points being bass and midrange. The bass isn't basshead level or really that prominent per se, but it is very nice. I find that it is relatively level with the mid range, with the mid range standing out a bit as being more "forward". But the midrange doesn't really interfere with the bass. It is almost as though you hear through the midrange to the bass. The bass is relatively tight with a thick sort of "round" note hitting impact. It doesn't sound incredibly fast or precise, but it also doesn't sound at all muddy and inaccurate. Overall it is a pleasing, smooth bass that transitions nicely into the mids.
The mids, as many shure fans know, have a lusciousness to them that really pulls out information in music that many phones don't really render well. They do this in a musical almost artistic way. I say that meaning that they aren't strictly realistic sounding, but rather almost "colored" sounding, in a good way. Like comparing a painting to a photograph. The photo looks real, but the painting can still be very beautiful. Overall, the midrange is really the high point of this IEM, and from the things go south. Literally.
The treble takes a pretty big nose dive right as it starts to become "high" treble. I sort of drops like a roller coaster. It slowly starts to fall and then vwoooosh, it's gone down the chart. ha. To me, this it the crutch of the 535. It takes away all sense of real airy-ness and depth of soundstage leaving things sounding sort of soft, padded and lacking clarity and pinpoint details. The 535 still outperform a lot of other IEMs, and surprisingly pull out a lot of details in music despite this setback. However, for mer personally, the treble is the reason I wouldn't use the 535 as my own IEM. I'll be honest though, I'm sure some people might not even have the best hearing over 10khz so this may not be a problem for a certain group of listeners, and the positives of the rest of the spectrum would definitely be pleasing for most.
However, that is not the case for those who can hear up to at least 16khz. I think you'll find the rolloff to be noticeable. Not to say that everyone will steer away because of this. They are still a very nice sounding IEM, and for some the other areas may outweigh the treble deficiency. For me, that just wasn't the case.
I would rate these are very high quality, very good at retrieving details and just plain fun to listen to. They only suffer from a lack of true "realism" and a noticeable treble rolloff.
As for accessories, the case and tips are pretty nice. The cables of the IEM seem very durable but add a little heft. I didn't find this to be a problem. However, the other major detractor for me is the size of the housings. They are very very close, but simply don't fit my ears without putting pressure on my outer lobe that very quickly turns into pain. Not just discomfort. For that reason, I would recommend these only to those who don't have small ears, or simply try them first and make sure they fit without pain for at least 30 minutes or so.
For more details and a visual look at the IEM feel free to check out my youtube videos:
Overview and Accessories: