What rock did you climb out from underneath that you have the notion that a 3 year old stale browser would have better web standards support than a fresh, constantly updated browser?
three words for you: BOX MODEL HACK if you don't understand look it up.
I have never used Avant, nor do I follow it, but to make a statement such as copying many of the features long offered by Avant you must be willing to provide some back up to that statement, because I am pretty sure it was not the first (thus implying its own copying).
Finally, even if you utilize one of these add-ons, you still deal with the bloat, the problems, the random crashes, and all the other good things IE represents. Mozilla/Firebird you start in a clean, isolated, and updated application.