It's a nice overall sound, though I think a bit too muddy in the denser parts. Softer parts are very good.
On my office (consumer) cans I don't hear any phase issues. I can clearly locate the piano in the middle, and lots of room and some audience noises around it. Sounds like the second piano is behind the first.
And that's precisely what I'd do a bit differently in this case. As we have two pianos, even I would go off listeners' perspective (although that's what I normally prefer with pianos - no good in having the high notes on the left and the low notes on the right or vice versa), and mic them from the tail ends. Not too wide spaced though, cos I wouldn't want them to be fully spread between the speakers. If I had the opportunity to record two grands next to each other (with the keyboards at the same side), I'd probably try a threesome with 2x 3ft spacing as a starting point.
Microphones always make me sound louder and better! -- Guitar Girl