I think it depends on the game. If it's just your average, run of the mill town/apartment/etc game where there isn't anything specific going on plot-wise, facts are fine because it's just a 'whatever happens, happens' kind of place. A detailed, 12 paragraph biography isn't really necessary and facts will provide the basics for players and moderators.
But if it's a genre game or a plot-based game (like scifi, mafia, zombies, etc), I think a biography is more important. You have to include lots of information like how and why they're connected to mobsters or where they were/how they handled an outbreak, etc. That sort of thing lends itself to a biography better than just 'everyone lives at Sunshine Apartments!!'
Personally, I prefer biographies over facts because I really enjoy creating characters and fleshing them out. I use bulleted fact points as a way to guide myself through a bio, so I always feel as if my character is left unfinished when I just list out a few sentenced facts. When I DO have to use facts for applications, each of my facts are 3-4 sentences. :/ I can't help myself. I'll be like "He has a tattoo of this in this location. He got it when he was this age because of this reason. While he has to keep it covered up at work, he likes to flaunt it whenever he has the chance because he thinks he's bad ass." Or something like that.