Pianoteq is definitely putting out some pretty high end work. I've been more impressed by the past two pianos than I had thought I would be. Loved the Bosendorfer and now really appreciating the new Kawai videos I've seen.
Roland's Earth piano sounds pretty good to my ear, too.
My biggest complaint with external sounds is that they're... external. Now IF, for instance, I could just load whatever VST I wanted to onto my RD-2000 and it was now onboard, to me THAT would be something pretty incredible. For studio stuff, it's not important. For gigging, though, simpler is better.