My current favorite for budget waterproof binoculars are the Canon 8x30 waterproofs. They are a steal at about $150 mail order. They are not built like high-end binocs (obviously) but are very good optically.
I am a fan of mid-sized binoculars, and several times have compared glasses with 30mm objectives with those with full sized 40-42mm objectives of similar quality construction. I honestly cannot perceive a noticeable difference in brightness, and this is confirmed by some comparison tests by Steve Ingraham of Better View Desired.
By the way, we should all have moment of silence for the passing of Better View Desired. This was the "Consumer Reports" of birding optics, and an invaluable source of objective information about binoculars and scopes. It never took off however, and after a several year run I recently received notice that no more issues will be forthcoming. It is a significant loss to the birding community.
Jack Stephens
jsteph02 at sprynet.com
Edmonds, WA