I haven't tried any of the plastic in my USS-64 but I bet almost all of them up to 20 oz. size would work. I look at the different drinks at Costco and all of the flavored waters, green teas etc would probably work. But why have a bottle opener on the machine if you are not going to use it!
I like dropping in the .35 cents and getting an ice cold bottle of Coke! Something about that "phfttt" when the cap comes off and the clink when it drops into the cap catcher that can't be replaced by a plastic cap being twisted off of a plastic bottle.
Tim