So I bought the W3 a few months ago and simply loved it. Great bass, nice highs, slightly recessed mids, just an overall fun IEM. I got an itch to try the new 535s, and all I can say is that the W3s are not seeing much use lately. The clarity and midrange on the Shure's is just awesome, a bit larger soundstage than the W3 as well. The bass is there when it needs to be, and is never muddy. People usually equate bass with "fun", but to me, these forward mids and clarity are pretty fun as well.
My only gripe is that I'm not a fan of the memory wire, and combined with the swivel action of the earpiece, they can be a bit tricky to get in. Also, as it gets colder outside, the thick cable gets less flexible and can be a bit awkward. For comparison, the W3 with Complys are a breeze to get in and the thin (but strong) braided cable only adds to that. I'll probably keep both as they are a nice compliment to each other, but the 535 is definitely a winner and my favorite right now.