They look about as similar as... I dunno, Marth and Ike. It's not a palette swap; there are very big differences, for both the immature Prime 2 incarnation and the fully-formed Prime 3 variation.There really is not a "big difference". On a glance they look pretty much the same despite the colours. Marth and Ike comparison is pretty good actually since if you make them stand next to Samus and Ridley, the latter is much more visually interesting and distinctive.
"Multiple exclamation marks are a sure sign of a diseased mind."
"Okay, okay. So you put a Nazi on the Moon. Fuck you, Moon."