Some of the built-in stuff is quite good, but there's a whole lot missing. For me, it would be the sample players (Kontakt, Play, SINE, ARIA, and whatever Spitfire's sample player is called), Pianoteq, spatialization, reverbs, some of the outlandish plugins, iZotope's stuff, a PSP equalizer, and a few synths. I know other people use a wider range of plugins, and they depend on them in their workflow. They are quite likely to bail to Cubase on Windows if their plugins don't get ported.