We've got some tripods, but find that the ball-valves break pretty quickly.We've had to replace 2 already and we haven't had them a year yet.
We've also got some galvanised buckets which are great. They look like a normal bucket with a funny lid. They lie on their sides and are very easy to fill. Not too sure how much they hold though.
They're great for the Turkeys, Geese and Ducks too.