I gave up on hydration packs. The water tastes horrible and it's tiring sucking on that hose.
I followed Kalama to the water bottle waist pack. It tastes so much better and I can just grab any bottled water and stuff it in the pack and go.
I use the Osprey. There is a bungee loop you pull over the top of the bottle that keeps it in place, even when a wave takes you out. It's easy to flip the bungee off and take a drink while standing. I'm not racing with it, just downwinding for fun.