Eh. Personally, I find Sheik to be Falco's easiest matchup, aside from maybe other Falcos.
The rest of the matchups down the line all have their annoying points. I'm also not taking low tiers into account.
Fox can gay Falco in many different ways, and also has a simple 0-(death?) cg on Falco.
Falco - Whoever can combo/DI better will win.
Sheik - You can combo Sheik easily, and proper DI can save you from the gayer combos that Sheik will attempt to string together.
Marth - Sword's annoying, 0-death CG is annoying, his edgeguard is annoying.
Peach - Dsmash. 40-death CG, turnips, aerial superiority.
CF - nasty tech-chasing game, knee nets CF early kills. Also has Falcon punch combo D:
Samus - Difficult to kill. UpB out of shield neutralizes pillaring. Missiles can be a pain, so can her tilts and aerials, not to mention fsmash/dsmash.
Ganon - You may THINK Ganon's easy to combo, which he might be, but a properly spacing Ganon is a ***** to play against.
Doc - CG, cape, bair, pills.
So IMO Sheik is one of Falco's easier matchups, and Marth would be one of the more difficult ones.