It's kinda like comparing apples and oranges - two totally different experiences.
If you aren't any kind of rush to get through dinner, Teppan Edo.
If you would rather get in, get your food, and not have to wait, Cape May.
If you have been to a hibachi-style Japanese restaurant before, try Cape May.
If you really, really like seafood, Cape May.
If you don't like seafood, Teppan Edo.
If you don't have your own vehicle, Teppan Edo (because it's kind of a pain to get to the resorts if you are relying on Disney buses).
Not sure if I made things any easier for you, but that's my 2 cents!
We went to Teppan Edo before they refurbed, and it was basically like any other Japanese steakhouse we've been to. Really good food, nice ambience, but it wasn't a unique experience for us. We tried Cape May the week of May 3rd and absolutely LOVED it. We really dig crab legs, and they had the best ones we've ever had - very fresh (yeah, I know they come from Alaska, but they sure were fresher than other places we've had them!). We had our own car, so getting to the Beach Club was not an issue. If we had to rely on the buses, we'd definitely think twice about resort-hopping to go to restaurants!