I have been running both IE7 and Firefox for a while now but lately I have gone back to using Firefox almost exclusively again. Functionalitywise the programs are quite similar but there are some compelling features that makes me stick with Firefox. Rendering speeds seem equivalent on my hardware.
- Instantaneous back and forward buttons. Many argues that this wastes a lot of RAM, but for me it is a perfect feature. I often find myself going back to something I just looked at a couple of minutes ago and in IE7, the reloading part makes this much less enjoyable.
- Adblock. Admittedly not a Firefox feature per se but still a very, very nice extension.
- Session handling. I usually have a lot of open links and I like the ability to just shut down my browser and have it reload the tabs automatically when I open it anew.
- Spellchecking. A nice feature as well, even though I find it a bit too tedious to switch languages.
- Multiplatform. Not a big deal to most people but I like to use the same software on my Windows and my Linux computers.
The only thing on the top of my head that I like in IE7 and which is not available in FF is the fonts. I love the look of the default font in IE7. Anyone who knows if that can be used in FF? It is very easy to read.