AdBlock is one of my favorite and most important add-ins. NoScript and cookie blockers run a close second. Unfortunately, there doesn't seem to be anything happening for Firefox mobile in cookie blocking.
Firefox on Android has always been a mixed blessing for me. Firefox is my favorite browser by far, but it has been an unmitigated disaster on Android. It's my favorite due to plug-ins, which really should be standard on all browsers by now. But Firefox's performance on Android has been sub-par, to be more polite than I have ever been on this blog. Even on my HTC Sensation it's slow. It's also a resource hog.
Seven does seem a bit faster and more polished than the previous version, though, so I added some extensions and did a small amount of browsing. One of the options is to reformat text when resizing, which I checked. As usual, there were a few options that should never be checked by default, like remember passwords. There is an option to delete all info on close, which should also be standard in all browsers.
Just for fun I popped up Opera. ThermionicEmissions loaded so quickly it made my head spin. While I did not time loading, it was appreciably faster than Firefox. The site was never loaded before in either browser, so there was no danger of it being cached.
I tend to use Opera as my default Android browser and it appears that it will stay so. I'm not crazy about the built-in browser because it feels very limited. On my first Droid, I tried a number of other browsers, like Dolphin, but I found Opera to be the fastest. Dolphin has all sorts of gee-whiz features but they're not so gee-whiz for me if I don't use them.
Speed is very important to me with Android, moreso after I switched from Verizon to TMobile. If I have to wait significantly longer for pages to load, a browser is of very limited use. I'll keep Firefox around just in case.