Apparently 'valgrind' is also ported to OS X, I wonder how it compares. (I haven't been able to use it yet because I'm working on a 32-bit project for an older SDK and it seems that 'valgrind' is 64-bit and using the latest system.)
But it's mostly experimental and not as easy to use as dtrace/lldb. What's more, you can't attach to the device, although there's a way to attach to the simulator — not for the faint of the heart.
