I have been using SGS3 for a week now, and wp8 has nothing which SGS3 and high end android devices would not have. I would not change to N9 either.

SGS3 and ICS is amazing. I probably stay with Android now at least until Tizen becomes ready or to a beta stage. I've found alike android app to almost all my most important N900 applications. Multitasking with SGS3 works better than in N900, no problems. One can have 3 active background processes from the settings, so having "fake" android multitasking is not a problem. I haven't had to reboot device even once during the week, when N900 had to be rebooted every couple of days after heavy use because RAM and system got fragmented and became stalling.

wp8 has lost the competition already before the birth.