What were the Megaraptorans?

A couple of years ago, Fernando Novas put forward a radical hypothesis: that South America's dominant predators in the latest Cretaceous, the megaraptorans, were not neovenatorids, allosauroids or even carnosaurs, but coelurosaurs in the Tyrannosauroidea superfamily. He considered this to be evidence that dinosaurs were in decline towards the end of their temporal range, with carnosaurs added to the list of fauna lost before the K-Pg extinction. 

Shortly afterwards, Andrea Cau stated that the anatomical similarities in the hip bones which led Novas to his conclusions were more likely due to convergent evolution than to any phylogenetic relation to tyrannosauroids. He also pointed out the fact that Aerosteon more closely resembled the Cenomanian giganotosaurines than Neovenator itself, and reclassified Megaraptora as a subfamily of Carcharodontosauridae. Thomas Holtz agreed with Cau on the issue of convergent evolution, but still believed Megaraptora to be part of Neovenatoridae. 

So, what do you guys think? Where do these theropods fit?