Ok here goes initial impression. Keep in mind, I've had the se530s for a couple years, and really loved them. I've been using a trimmed triple flange (I trimmed the smallest flange off and part of the stalk) and isolation is great, so I just moved those tips over to the 535s. Just like on the se530s, it takes a TON of force to get the pieces off the nozzle, but I was able to do it without breaking it. Easy does it...
On another note, I was actually disappointed when the fedex guy came, because he ONLY had the se535s and not the custom tips I'm waiting for (they are made by westone, so they are probably the ones linked to in the above posts). It's been two weeks (I had the impressions done two Fridays ago) and I was told it should be only two weeks, so I'm a bit disappointed about that. Hopefully fedex doesn't deliver them like I was told, and instead the USPS guy shows up with them in the next couple of minutes.
With all that out of the way, my initial impressions of the se535s are very good. The construction is VERY solid, even compared to the se530s which I thought were themselves pretty solid. The cables look indestructible, and the clear housings are so sexy I can't wait to walk outside with them
The fit is (if possible) even better than the 530s for me. They rest so close to the ear that I will find them even more comfortable to sleep with than the 530s.
On to the sound...
Obviously, these are the se535s, so they sound VERY similar to the 530s. One thing I noticed is they seem to be a tad quieter than the se530s. I could be imagining things, but that's what I hear. This is not a problem, as the 530s and the 535s can go louder than just about anything I've ever used. I'm not what you would call an audiophile, so I'm not sure I quite understand the meaning of words like "sibilance" and "rolled off highs." What I will say is that on the 530s, the highs sometimes seemed a bit harsh (the clashing of cymbals, for example, sometimes seemed overstated and kind of annoyed me). On the 535s, I don't hear that as much. To me, the 535s are a nicely souped up version of the 530s, and I do not (yet) regret purchasing them; I doubt I ever will. My 530s will have to find a new home (I will help them out of course!)
EDIT: Don't they just look so happy in my ears?