Some good stuff, some bad stuff, some apathy...
First I visited internet newspaper First Post, where I've never been able to play the videos in IE7 - and it has never told me why. To be fair I haven't looked that deeply into it, but when I visited in Firefox it told me the problem! And I fixed it! And I got to play videos in the First Post website!
Sorry about all those exclamation marks.
What about speed? I noticed no appreciable difference, but of course being on a corporate network with a massive pipe (like Sherlock Holmes's, but not a Meerschaum) I didn't suppose it would. Perhaps I should try it at home as well…
One thing I was worried about was importing favourites, but again Firefox just asked me if I wanted to import them (I did) - and then just went ahead and did it. No fuss, no hassle, no strange dialogue boxes. However, it doesn't update the favicons in the window till you've been to the site in question, but this is a minor hassle.
One problem with Firefox - getting new tabs open is weird. You need to go to the File button and add a new one each time, or right click and select New Tab in the browser window. Unless you 'open all your recently bookmarked sites', which will launch a veritable plethora of tabs. Of course in IE you just need to click in the space next to a tab and a new blank one opens - there's even a little ghostly one waiting.
So would I change? Well IE7 costs and Firefox doesn't...and I am notoriously tight-fisted. On the other hand I'm not paying for my Windows, lucky old BCS is! But then there's the moral dimension - open source just seems a better principle doesn't it? (Is it open source or just freeware? Either way it's free, eh?).
Decisions, decisions. This will probably go to penalties.
Final score: Firefox 3 IE 2.