The rigid back of the Osprey is very good at keeping the pack flat.
Bite valve is great.
Magnetic bite valve great but pack specific I think.
Antidote reservoir good, quite ‘sausagey’ compared to the Osprey. Quick release hose useful if the hose is hard to remove from the pack – but this empties the hose contents when disconnected so can be a pain.
I was gonna post essentially this but gravity-slave has saved me the trouble. Absolutely spot on. I’d just add that the newer antidote Camelbaks can be opened with a quarter turn which is a massive improvement over the older style super, uber tight caps. The rigid handle on the Osprey makes filling much easier, as someone else mentioned.
So, if you can get one in – Osprey. If not, Antidote…