Falco is a better character, but Falcon is cooler. Falco has a bunch of guaranteed stuff, a frame 1 move that can combo really well, pillaring can rack of tons of damage really fast if the other person doesn't know how to SDI out of it, lasers restrict the opponent's movement and puts them into stun for followups, and his Dair is one of the best gimping moves in the game. Falcon has the best movement in the game (in the right hands), has super hard punishes, has some guaranteed stuff but percent memorization is super important for proper follow-ups, he can combo most of the cast really well (if you know how to do so), takes longer to die off the top since he's fat, but also has one of the worst recoveries in the game. I'd just pick the one you have the most fun with.
