I've always preferred FF. But speeding it up a bit is just another reason to like it and perhaps eliminate one major complaint others have had.
(On the other hand, I do admit that FF seems to be going in weird directions at the moment, such as having a new full version number-- apparently now I'm at v15 or v16-- every couple weeks. And the more it starts to become like the other browsers and do weird things, the less I like it. But having the option to override these things is good and overall I'm not planning to switch from it.)
I did install Chrome and Opera the other day to do some testing though. So maybe that's my first step away from Firefox. Not for the moment though