I understand it probably handles mutithreading better and probably has a much better performance - but is that really it?
There is also the advantage that perf is really testing the actual code on the real hardware. This can get important if you are trying to design code that is cache-aware. Although, with cachegrind, you can set what kind of emulated cache parameters you want, I'm not sure how well this emulates the real hardware, especially if you have multiple threads with cache conflicts.
edited: typo
{
tracer tr(function, ...)
timer ti(tr, milliseconds);
I love valgrind/callgrind and it has proven extremely valuable. As always, choose the right tool for the job.