I use BB online only because i've been a member since before the dawn of time and get 3 out at a time, unlimited returns in store, and 2 free game or movie coupons everymonth for less than 20$ with tax. (netflix can't touch that)
especially since If I rent 2 games a month, it pays for itself.
That being said, netflix is faster, but I really like the instore trade in. Sometimes i get movies just to trade instore to get new releases faster.
I really really wish they would get of their asses and rent hd-dvd in store as well.