I hated them for gaming when they first came out, but the Logitech MX518 finally won me over.
It's longer and taller than the MS Intellimice I'm used to using so I had to get a wrist-rest. However, after a week I'm officially mechanical mouse free.
I think my UT3 scores might have actually improved, and I love the extra sensitivity for desktop use.
Best part is, no more cleaning those rollers. :-)