Bank A and combi presets are glorious, GM bank presets are ok for the most part but some are horrid. The manual is incredibly complete and detailed but not for the faint of heart. For the most part, getting around the operating system is fairly easy. I'm not aware of any OS upgrades. Only one stereo pair of outputs though.
Electric pianos are passable, brass sections kind of boring.
Some wind instruments are great, others are lame. It's possible to wring fantastic subterranean ambient noises and all kinds of weird clangy things from this synth. Drums are overall really good. The FX are tremendous, clean and airy. A very capable synth that sounds wonderful.