I mostly listen to rock (U2, Tom Petty, Bob Dylan, Buckethead, etc) and classical (Yo-Yo Ma, etc), but also blues (BB King, Albert King, etc) and some electronic & rap (Prodigy, Jay-Z, Beastie Boys, etc).
Overall, this is a fantastic IEM. The highs and mids are amazing and the bass is adequate. The bass has been discussed fairly extensively in the forum and while I agree that a bit more punch would be nice, the detail of the bass provided is superb. The highs are in no way too strong or aggressive. And the mids are as great as others have said. One aspect that I really appreciate is that the vocals shine and are exceptionally audible compared to other headphones I have owned (Denon 5000s). I am finding myself actually learning lyrics that I didn't know previously just because the detail on the vocals on the reds is so amazing.
I now have about 50-60 hours on these and I have seen a slight improvement over that period of time. But the first 10 hours probably made the biggest difference, with the IEMs opening up quite substantially during that period.
I previously owned the regular SE535s and sent them back to Amazon to order these instead. Overally these are marginally better (esp highs), but I would not recommend a replacement of your SE535s unless you are an extreme audiophile and listen to alot of classical music.
Until now, all of my headphones (Denon 5000s, regular SE535s and these) have been used on an iPod classic with the regular headphone jack. I have ordered a Pico Slim and can update my review once listening to the reds on the Slim. Truthfully I'm a bit skeptical how much the reds will improve on the amp because they sound fantastic already.
All in all, you can't go wrong with these IEMs. If you desire super punchy bass then perhaps you would want to look elsewhere. But if you appreciate nuanced bass (even in songs from groups like Prodigy, Beastie Boys, etc), then you should go with these.
I want to provide an update after listening to these with the Pico Slim and the SR-71A amps. Although the Pico Slim has the upper hand in resolution and clarity, I think these pair better with the SR-71A. The Pico Slim is known to do well with mids and highs and these happen to be the strengths of these earphones. When paired together, however, there was an edginess and strain to the highs, almost to the point of being hard to listen to with some tracks. On the other hand, the SR-71A and SE535LTD red combo seemed to be more complimentary, with the SR-71A providing a nice boost to the bass while not undermining the mid and high strength of the reds. The highs are a bit smoother than they are coming staight out of the ipod jack and don't have the edginess to them that they had when coming from the Pico Slim.