I recently upgraded to Firefox 3.6. The only thing new that I have noticed is the new Personas feature. Which basically just allows you to put some image near the top of the browser around the address bar / tool bar area. Nothing exciting and some images just don't work that well in terms of being able to see the rest of your menu items and such.

Firefox does claim 3.6 is slightly faster than 3.5.

I mainly use Firefox because of all the free addons available that Internet Explorer and Chrome just can't come close to competing with. After upgrading, there are a few addons that no longer work. Usually the addon maker has to make an update, which usually doens't take too long.

One of the drawbacks to both Firefox 3.5 and more so in 3.6 is the amount of memory it consumes. After starting Firefox 3.6 it consumes 100-150 mb's. Shortly after browsing around other sites it quickly jumps up and continues to build. Earlier today it was up to using 550 mb's of memory. This is just way too much for a simple browser. It could be some of the addons I have installed contribute to this, but still at 550 mb's it's a little more than average.

I really wish Firefox would work on some memory tweaks when they put out a new release, rather than adding something like the Persona image option.