Bugzilla does have a email interface. It needed some hand-tweaking when I set it up a year or two ago, so I cannot vouch for its condition, but it is there.

Bugzilla also has an interface for customization. You can have separate products (like "queues" in RT), and you can further break them down into components. So bugzilla is more flexible there.

Bugzilla allows you to set the default bug owner by product/component. We use a fake "bug" user, and assign someone to figure who should solve the bugs.

IMHO bugzilla is more user-friendly, and allows the user to customize their own stuff more, such as how their own list of bugs is displayed.

I have not setup RT, but I suspect is may be easier, precisely because there are less customizable options. RT also has some nice built-in knowledge-base functions.