Have you tried "orca", Nibs, on the same page.
I ran them side by side. The only real difference I could see is that avant was a piggy back of IE (plus some very usable features), whereas Orca does appear to be an attempt at a self sufficient browser.
Certainly, once you have ploughed through all those options, it does have a lot of merit.
I loved this one (for my purposes!!)
bookmarks.rar
Ha! Got it. Orca is very much the same idea but based on Firefox. It seems to be more complete than Firefox, with all the popular add ons.
Both, on impressions only, seemed to be at least as fast as IE or FF. One downside on Orca is that nothing seems to have been done to it since 2009. Avant is still being developed.