I have not tried the E5 (though I am tempted at times), but I have recently upgraded from the E2 to the E3 and I'm sure that you will be more than satisfied with the sound you will get from the E3.

My only caveat would be that if you've never used in-ear phones before, they will take a little getting used to. In the beginning, I fussed with them quite a lot, but now, I don't give them another thought. I use the foam inserts and get great isolation on plane rides(I'd even be willing to sit within two rows of an infant now).

I've also read and found myself, that there is a "burn in" period in the beginning, where the phones sound subdued. After listening to them for a while, you will notice one day that they sort of "kick in" and all of a sudden sound really great. I took mine straight away and plugged them into my stereo and left them playing off of the radio, at a high volume, for a day or so before using them. That seemed to shorten the "burn in" time.