I'm just going by the Smash Wiki on this one. One move has a smaller hitbox (meaning it's less likely to hit), one move has significantly less knockback (making it harder to KO with), the arrows are harder to control than Pit's, and the Electroshock Arm does slightly more damage and knockback. (then there's his final smash, which is completely different from Pit's but is basically a copy-paste of Zelda's)