Ive used this browser one helluva lot. Earlier it was called phoenix but they had to change the name cuz some companies were shouting copyright infringement.
Ive downloaded each and every build from 0.1 to 0.6. The features added with each build were astonishing.
If youve used Mozilla before - believe me - Firebird is godsend for you. Blazing startup - nift features, small memory footprint. This is the best browser that you can have.
I dont know how it compares to IE - but it does have some nifty features which might get you addicted:
I used to swear by Firebird (erstwhile Phoenix) when I was using IceWM but I switched to Konqueror though, because of its tight integration with KDE. But still, I dont have to think twice to call it one of the best browsers out there.
Go for it! Especially if youre on Linux!
(If youre on Windoze - may god save your soul :)
Nandz.