They are a new headphone, so reviews won't come out too quickly (or as large in number). As far as I'm aware of right now, I'm the second person on the forums with a pair of these. No in-depth impressions have been given, keep an eye on this thread though: http://www.head-fi.org/t/610966/new-pioneer-se-mj751-bass-head-headphones
Make that one of three people as I just got a pair of these about a month ago. HiFiGuy528 has the Japanese version I think. I have the STEEZ-branded U.S. ones like yours. I must admit though that I haven't been able to spend nearly as much time as I'd like to with them - much less burn them in. I've just been way too busy lately. But from what I have heard, you were pretty right on.
@dcsquirrel - I wholeheartedly second these. They offer much of what people like about Beats, with far less drawbacks. If you're interested, tinyman392 really did put up a nice and thorough write-up about the 751s in the thread he linked to. And with the exception of the P3 and Tracks comparisons (mainly because I have not heard them), I pretty much concur with his assessment.