The 51S715 has a USB input for an external USB reader (not sure how that works). The 51S700 has some sort of PC card reader built in. I'm not sure that one is better than the other.
I guess I should have clarified. It does not list 540p as an acceptable input format for the 51S715, but the 51S700 does.
I see firewire as the only notable omission.
Does anyone know which set in Mitsubishi's lineup the 51S715 lines up with? It seems like it's sorta in between the WS-55615 and the WS-55815.
I got tired of waiting and called Hitachi after they didn't answer my email (Circut City didn't answer either). The CSR rep checked and told me the new models will ship in August. He had no date or other info. I could have guessed that.