A complete firefox rip-off, except that it's laggy, buggy, vulnerable to hackers and fail to apply web standard. and oh yes, it completely sucks.
Frankly it's just the ie6 engine with a fancy new GUI.
ie guy: "look, Internet Explorer 7 is sooo much better than firefox, and it has coool tabs too"
you: "are you stupid or something?? firefox have had that since many years and microsoft is just stealing that because the people are stop using explorer, and mozilla care about w3c too"