Hate to say it, but I used to have the job of testing on Firefox and (at least at the time) no, Chrome was the best.
The number of irritating little performance regressions we'd hit when doing anything interesting with the DOM in Firefox was notable (as in, we noted it in the bug-tracker ;) ). Broadly speaking, I began to assume Mozilla didn't have enough real-world integration tests back-stopping changes to their rendering engine.
I haven't tested in a few years so that information is stale.
The number of irritating little performance regressions we'd hit when doing anything interesting with the DOM in Firefox was notable (as in, we noted it in the bug-tracker ;) ). Broadly speaking, I began to assume Mozilla didn't have enough real-world integration tests back-stopping changes to their rendering engine.
I haven't tested in a few years so that information is stale.