Well I know all the pro stock engines do this. Probably all the comp and SS guys as well but is it worth it for a street engine or a bracket engine? Probably not unless you are scratch building an engine anyway. In a small block I think the 48* tappet angle is worth more than the 4/7 swap but if you are custom ordering a cam anyway, why not go for it. I wouldn't swap cams in a running engine for that reason alone.
i guess along with valve angles too. ie chevy's 23deg(stock) heads vs mopars 18deg(stock) heads. i have no idea what what valve angles on a ford heads are. i watched alot of youtube vids (all chevrolets mind you) the sound healthy enuff. i dunno.