I love my Camelbacks. I primarily use the "blowfish" because I can carry extra stuff that I use on longer trail rides. I was recently given a small Camelback, "flashflo"; it has a bladder (45oz) plus a place for 2 bottles on the sides. I can carry a bar, keys, some first aid stuff in its pouch for short rides.

I would find it "hair-raising" to take my hands off the grips to reach for a drink from a bottle on a mountain bike ride. The Camelback takes one, fast, easy move to get the spout to the mouth...less time and effort and you can drink while you ride with both hands on the bar. I only use bottles in spin and if I wouldn't get "stared at" I'd bring the Camelback to class!

I did have a Platypus but, the second time I used it, I had taken a fall and it burst open. I took it back. I didn't find the seal to hold under impact. I think the Platypus is great for hikers.
Terry