I think it's the enterprisey configurability really. A lot of the instances I've had to use were confusing messes with local OK parts, I wouldn't be surprised i

I think it's the enterprisey configurability really. A lot of the instances I've had to use were confusing messes with local OK parts, I wouldn't be surprised if some combination of configuration yielded much better usability. Bugzilla is obviously very ugly (and directly out of the 1990s) but it does work pretty well and it's fairly logical to use.