I haven't cleaned the drinkwell yet, so I don't know...
The Petmate I had to refill every day. It is easy to clean as long as you have a brush - I use a baby bottle brush. It is not hard at all... The drinkwell Will hold at least a week with my three cats, but one of them barely drinks, since she eats all wet....
So I would say a week for 2/3 cats, since you need to clean weekly, even though it will hold more water than that... I filled mine on Monday, it is barely half full...
