Does anti-aliasing work on iphone 4 and ipad? Is it fast enough to actually use?
It works, but it’s very heavy on the hardware. Tried it (2X) on the iPad and my framerate was halved, went from 60fps to sub 30 (simple scene but 40+ object moving, particles and around 5k vertex).
I think it’s usable in some cases (simple scene, not framerate critical) but you need to be very careful. It’s barely noticeable on the retina display, but the effect is great on the iPad. 
http://forum.unity3d.com/search.php?searchid=605961
http://forum.unity3d.com/threads/77446-Unity-3.2-built-in-MSAA-much-slower-than-forum-user-hacked-AppController-MSAA?highlight=msaa
it is not that bad, we screwed one little thing and intend to fix it
any ETA on when the fix will be implemented?