Very useful and easy to use. Have tracked down a big leak in one of our applications which was a gradual leak over a few days of running, causing us to run out of memory.
Biggest issue I've had is that its failed to take snapshots on a few occasions due to errors such as 'unable to find class' errors which don't kill the mem profiler, but do leave the snapshot buttons etc disabled. I've send a support request regarding one of these to you.
And earlier today, the mem profiler died completely when taking a snapshot.
These don't seem to be reproducible though as I'm running in a virtual machine, so I take a virtual machine snapshot before taking a memory snapshot and if the snapshot failed, I revert the virtual machine and take it again which seems to work.
But they are an issue as we have to run for about 12 hours between taking snapshots and if mem profile dies, it can delay us a day.