My FINAL experience with JIRA + Fisheye + Greenhopper + Crucible nearly made me cry. This is on an 8 core Xeon, 12Gb RAM, 15k SAS RAID and Ubuntu 10.04LTS and Sun hotspot VM.
Random failures, null pointer exceptions all over the place that took us out for a couple of days, incredible memory usage, 8xCPUs jammed at 100% due to race conditions, Fisheye only barely just about works in Google Chrome because it's so slow, useless paid support, horridly slow and inconsistent UI, MyISAM tables causing relation failures (!!!!), don't even talk to me about their plugin management - it's a crock of shit.
I couldn't recommend it at all. It's worse than Visual Source Safe.
That's as a JIRA admin. As a JIRA user, I get people saying "can we have Trac back please".
If anyone at Atlassian is listening, please sort your product out. It's not fit for purpose.