ORIGINAL: Bipe Flyer
I like the Hayes 2oz. It has a very small stopper with no rubber, the vent is moulded into the tank so there are no brass tubes. The fuel line that comes to attach between the stopper and clunk is black, very flexible and not silicone.
My only "beef" with the Hayes tanks is that you really have to mount them vertically, and that limits the number of planes I can use them in. I guess you could lay them horizontally, but then the vent sarts blowing out fuel when the tank is 1/2 full.
EG