Yes I helped Mozilla try and achieve the largest download in a day by downloading and installing their latest version of Firefox tonight. Just playing now and discovering the new features, Seems like bookmarking sites is one of the big new features with related links and a recent activity drop down. Being able to tag sites should also make it easier to find in future.
If you still run IE have a go with Firefox. It doesn't take long to get set up and knocks spots off IE.
Have you installed V3 yet? and what's your favourite new feature?