Fitness for purpose
Adamwill (talk) "Most of the other free bug / issue tracking systems are a poor fit for a distribution managing a large number of components that additionally have their own upstreams." - well sure, but then so is Bugzilla. We just got used to it. But it's not designed for a Linux distribution at all. It's really not meant to cope with a 10000-item long component list, for instance - one of the major sources of slowness of our BZ instance. It basically has one fewer 'product-ish' field than we need, so we can't split the bugs of large source packages up: this is a major and ongoing source of problems for the kernel team, for instance, because we have no good way to file wifi bugs separately from graphics bugs separately from networking bugs separately from etc etc etc.
BZ has no kind of working upstream integration at all. The External Tracker thing just doesn't work and hasn't for as long as I can remember.
BZ has no sensible way to track the same bug across multiple Fedora releases.
I just don't think this is a plus point for BZ, at a minimum. We've gotten used to dealing with BZ's limitations in respect to using it as a distribution bug tracker, but its limitations are just as significant as any other general-purpose bugtracker's in this context.
I hate to throw in a possibly incendiary topic, but there exists a F/OSS issue tracking system which is specifically developed for use by Linux distributions, and addresses many of the limitations I listed above. It's called Launchpad. I note that it wasn't on the list of possible alternatives.
Kevin We did think about that, I'll add a note about it. ;)