<b>Falco</b>
I like Falco because of his much better spacing makes it hard for him to be touched and can chain nairs once he pops his opponent in the air. Most of Falco's moves leads to a spiking oppurtunity off the ledge, but if you can't quite get that spike, you can just bair them off stage until they die.
Falco's lasers imo aren't as great as Fox's because I personally have trouble getting them out fast AND close to the ground. They do however have stun power and can gimp recoveries when they're way off stage near the blast zone.
Falco's f-tilt and Down-B are great spacers. Down-B is a bit situational, but is very useful.
Falco's u-smash and and u-air aren't bad KO moves like in Melee and are more on par with Fox's.
<b>Fox</b>
Fox, in contrast to Falco, is faster. Fox runs faster, jumps faster, jumps farther, and falls faster. Fox's reflector is used to get out of your opponents pressuring as apposed to spacing. Fox has an easier time running about landing grabs which allows you to pressure your opponent a lot more since your opponent cannot always reliably hide behind a shield. Fox's U-smash and U-air are quick and powerful KO moves, and are easy to land and can be comboed* into. (*not always a true combo, but you can force opportunities none the less)
Fox's lasers don't stun like Falco's but can be used as free damage when you are far away from your opponent. Doing this also can convince your opponent to take the offense if they are camping a bunch.
Fox's b-air requires precise timing compared to Falco's but launches your foe more horizontally making it harder to recover from.