The only people with unbiased views are not subscribed to AH *or* WB and are probably F4 dweebs trying to figure out where the afterburner is on their prop plane. That having been said:
"Hit bubble" in WB? Wasn't that AW? Maybe someone is thinking of the time HS (not to be confused with HT, tho neither of em can spell) said there's a gross check for nearness to a plane and if a round gets into that region then a fine check is made to see if it actually hits anything and if so, what. That's not the same as a hit bubble.
Flight models are remarkably similar, except for the roll inertia thing. Early AH I didn't like (was that AH1.4 where it changed?) but now it seems HT and HS both did their math separately and came up with just about the same answer.
http://agw.warbirdsiii.com/bbs/showthread.php?s=&threadid=1526WB3 gets the edge on graphics, both speed and clarity IMO, but that's just eye candy. Definitely better on Macs hehe.
AH has larger planeset and MA strat thing and perk points, WB3 has rolling plane set and S3s and TFTs.
Whatever; for what most of the people I would call "vets" used to pay in an average week you could subscribe to both for a month.