Frame Rate Questions

Hi Guys,

I currently run 3 cameras, an HPX370, A 7D and a 5D Mark II. Typically I shoot in 1080/24p (pn) for film style shoots and 30p for commercials and broadcast. I was hoping somebody could clear up something regarding frame rate.

How come I read about so many people still using 720 as their main frame rate? Other than saving space is there some benefit to shooting only is 720? Is that still the standard even though cameras can shoot in 1080p at this point? Other than variable frame rate and shooting in 60p why do so many shooters still utilize this frame rate? Is everybody just that obsessed with overcranking/undercranking?

Any thoughts would be much appreciated.