Marth in Melee could deflect projectiles as well, I sucked against projectile-users when I was going FFA matches with my friends so I sometimes decide to burn Counter to inch me closer to edge range. Marth DID indeed deflect a fully charged Charge Shot from Samus but he 'knocked it away'.
If I recall, Marth did the Counter-activation animation and the big ball of doom went behind him in a diagonal path above, eventually dissipating. I did this with Roy as well except there is a higher probability he will actually deflect it back at the opponent, which won't hurt them strangely. Roy's goes diagonal as well but since he slashes vertically with Counter, you won't notice much of a difference in the 'counter'd' projectile.
Counter was on of my most favorite specials in Melee, and effectively using it has always been a challenge or a gamble. From what I've learned on Ike's Counter so far is that it's similar to Roy's, it has power and mild knockback.
