The discussion so far hasn't really discussed zoning in the sense that Vlade or HugS used it . . . .
But my two cents:
Advantage:
Grounded center stage -- This is a pretty good area to be in regardless of the stage choice or opponent. You can CG to the ledge without needing to do anything fancy. You're as far away from all the blast zones as possible. You can escape to any direction if need be. Your best kill move is Up smash and that's not affected by your horizontal position. I guess the down side is that lasers aren't as effective since you won't be at far distances and can't really SHDL so you won't have as much stage control. It's also a pretty good spot for MK and other characters to be in so they'll be "competing" for that area.
Left or Right parts of the stage facing inwards -- At a distance, it utilizes the lasers the most and SHDL are most effective. You can CG > RBPG to go for a stage spike. This usually isn't the best spot to be in since it's easier to be killed, but at least it'll limit the tornado and drill rushing. Once MK gets in close, this area becomes a disadvantage and it'd best to run away since a Dsmash or UpB won't have much trouble killing.
Neutral:
Left or Right parts of the stage facing outwards -- Lasers are useless. You need to either cut your CG short or do a double RBPG to really get all the damage out at low percentages. Falco doesn't really have a move that's quick and strong enough to force MK off the stage except maybe Ftilt or throws, but even if MK's recovering and you're at the ends of the stage you don't have an advantage since you can't gimp MK. And MK will use one of his B moves forcing you to shield or dodge. All of that sounds pretty bad, but at least MK doesn't really have an advantage either. He can't kill you easily if you have to fly across the entire screen. He'll just be staling his moves.
Disadvantage:
Off stage -- self-explanatory
On the ledge -- Almost as bad as off stage, but at least you have a lot more options. Still, it forces you to act and MK can react when ideally it should be vice versa.
Directly below MK -- MK's Dair is too good . . . .
On a platform -- You don't have any room to run. Can't CG. If MK is below you, he can UpB or just Uair through the platform and you can't retaliate. If he's above you, well . . . he's above you and he has his Dair that beats out just about everything. However, if he's for some reason grounded on the platform, it forces close range combat which apparently is in our favor because jab is amazing.
That's my opinion. I guess it'd be good to also discuss how to avoid/escape the bad zones and how to control/be in/utilize the good zones.