The only thing that puts me off Stash is that I'm a part time JIRA, Fisheye, Crucible admin (on site ~ 250 users) and my word both those things make me cry at least once a week with problems. If it's not dealing with the licensing hell and the tears of management when another $32k pisses down the drain on maintenance (mafia style protection) it's dealing with memory leaks, crashes and constant performance bottlenecks. And we run this on a cluster of three high end 8 Core/32Gb RAM/SAS disk HP machines...

I couldn't face Stash after that.

Edit: Atlassian support are excellent but we have to bug them too often with entire sites down (workflow consistency issues fucking the entire JIRA instance which happens at least once a month) for the product to be considered quality.