Heh. This reminds me of something.
Custom Robo Arena was the very first Custom Robo game I had even heard of (I honestly thought it was Nintendo's new thing, I swear), and thought the Robos on the front were the only three you could get. I was nervous starting up the game, 'cause I wanted to make the right choice, since I though it would be permanent, like PokeMon. I thought the game went like this:
Ray Mk III: The balanced one.
Rock Hound: High attack and defense, crappy movement.
Miranda: Quick as all get-out, but can't take/dish out a hit worth crap.
Put gear on it and hope you made the right choice.
I was relieved to find out that I was dead wrong about them being the only ones you can get. XD
Viva la Ray Sky and Ray 01!