Depends. Do you want to level professions? Do you want to sell stuff on the AH? Do you want to afk while you go make a sandwich?

My /played at 69 is over 14 days by now, but they all have leveled professions, exalted with kurenai (talbuks!), sporeggar rep aoe grinding shield, etc.

Do you want a well rounded character at 70 or a pretty much "naked" 70 character still wearing SM gear? Because one will be faster than the other.