Actually, it's often not performance that's the problem like you might be thinking. Some apps, for example, actually become faster with Obj-C 2.0 GC enabled, si

Actually, it's often not performance that's the problem like you might be thinking. Some apps, for example, actually become faster with Obj-C 2.0 GC enabled, since all of the retain/release message sends become noops. (Some will be slower, too, of course.) What you do definitely lose is easy predictability of memory usage. Memory usage can spike when you don't anticipate it. On a desktop this is no problem, since you have a ton of memory to work with, and if you do use too much, it just swaps to disk. On iPhone, if you exhaust the memory, the phone reboots. Oops. But I don't think GC is too far off for iPhone.