I’ve been hanging onto v.2 as some add-ons haven’t been updated.
On the other hand, I hope v.3 handles videos and audio better. Many news videos posted at TV stations just plain don’t load with Firefox and I go to IE immediately to watch them instead of waiting forever(and still not seeing them). Same with audio streaming of some of my favorite talk radio shows.
I use Linux but in any system it depends on what plugins you have elected to handle various stream types. FF3 did improve compatibility with many of those local site videos (generally using mplayer) in my case. It is rarely now that I can’t play one.
Search on “IE Tab” and Firefox - it allows you to open an MSIE tab/window in FF or go to 970wfla.com select “Listen now” and follow the Help prompts to install it. It fools most sites into responding as if you’re running MSIE. ;-)