I guess I'm from the old school, as I prefer number of chips. I don't know too many players that bet by big blinds, but everybody uses number of chips. I'm too busy trying to win hands, and I really find it annoying that I have to convert from BB to chips, to figure out how to bet, and what I actually have.
I find that Party Poker, really overdoes this. They actually switch back and forth during a tournament, and it makes me so put off, that I seldom play there, anymore. You're going along trying to calculate what you should bet, and suddenly, on the next hand, they've switched to BB. Now, I have to calculate how many chips that is, and even though it's simple, it's an extra step I don't need, when I'm playing.
At least, they should stick to one, or the other, and not switch back, and forth.