[Switchblade]

This is a tough one, all three are really strong. Black RX has some nice weapons and Biorider is kind of broken as hell. Agito is also incredibly powerful and Shining Form is probably one of the most powerful ultimate forms ever. Ultimately, though, I have to go with V3. He was built to have the combined power of both Riders 1 and 2, plus he has the 26 secrets, which include some really awesome and powerful moves. For my money, he's always been the most powerful of all the Showa Riders. He's also a really badass character and wouldn't hesitate to hold back.