In light of this recent development that's what I just switched to.

I was using the 64-bit builds over at http://wiki.mozilla-x86-64.com/Firefox:Download when Adobe first kicked out a 64-bit beta of Flash. Later I switched to the official Nightly builds when they went 64-bit.

Unfortunately I'm not able to offer much insight into if it was better. Aside from a couple of short strings of bad builds that caused crashes I never had any issues with them.

I've been waiting ages for Mozilla to get their act together and make a 64 bit browser. I had never heard of this before. I just downloaded it and I'm trying it right now. So far it seems great. All my extensions seem to be working with no problems and it feels like it's faster. Thanks for the link!

It is great. Speed alone would be a reason to change but the best thing about it is that it is not banned on my companys PCs as FF or any other browser then IE are. I finaly experience speed and adfree browsing again.