I'm a member of Sony X, so I get discounts on Sony stuff, it's slowly turning me into a Sony fanboy... Regular RRP direct from Sony is $699.
I don't get much time to listen to it in extended sessions, so battery life hasn't been an issue, and as such Wi-Fi has been left on. I imagine that pop-up would be annoying. I haven't had it during my bus commute to and from work, but that trip is only 30-40 min, depending on the day, so it might not be a long enough trip to trigger it. I swapped the Sony stock player widget with the PowerAmp widget when I swapped default players, it's probably the first time I've ever used the PowerAmp widget, and actually its pretty nice.
It's very possible that my UE TF-10's are the limiting factor, and the differences in players is minute enough that I can't hear it.
Other issues that I thought of though: the stock player seemed to have issues with ~70% of my album art, and I'm kind of picky about album art, it annoys the hell out of me when I get the generic grey icon where there should be art... What's even worse than the grey CD-box? The solid, brightly coloured squares with white text the Sony stock player uses when it can't detect album art - pretty hideous to me. The other little annoyance was that it seemed to be jittery with my inputs; some of my taps would register as slides, so sometimes I'd have to tap a few times before it's registered as a tap.
I'll experiment with the two later and see if I just didn't give the stock player a proper chance, if the SQ improves I'm willing to live with the annoyances since they all disappear if I keep the screen off and use the side buttons, which I do often anyway.
But as I said before, very positive initial impressions - the things I mentioned above are really just minor niggling things, and I'm very happy with my purchase.