Won't do much against a good Snake.
I'll mention some things about the matchup, which is definitely in Pit's favour in my opinion.
Pit's projectile game completely shuts down Snake's projectile game.
Pit can CG Snake to 40% with his Forward Throw.
Snake has trouble dealing with Pit's ledgegame. (Arrows, Uair and Nair from the ledge.) The wind effect from Pit's Up B enables you to push away Grenades from the ledge and there's always the Mirror Shield to reflect them.
Pit can gimp snake relatively easily if he can get him off the stage, but you have to be selective with which moves you use as moves like Nair and Uair will not hit him out of his cypher.
I'm a pit main that thinks the matchup is in snakes advantage. Pit has a lot of advantages against a bad snake but if your playing one familar with the matchup those advantages really dry up.
A nade hitting you does about as much damage as an arrow hitting snake and a grenade exploding does a lot of damage. Pit can beat snake in a range fight but its not a slaughter. My advice on that is don't be afraid to fight him range but don't count on it once a snake slows down and starts throwing timed grenades its quite difficult to deal with. Snake can approach through arrows without much difficulty so your going to have to do more then just shoot arrows.
If the snake knows what he's doing he can get out of the chaingrab after the second throw. Its not exactly easy and as I'm the pit in the matchup I'm not sure on the technicals but I think if snake di's down and away he can spot dodge before pit can grab again. Still it puts him in a position where you can follow up the throw easily enough.
Pits ledge game is quite effective against snake. You have to be somewhat careful a grenade can stage spike you easily if your careless. Also a lot of tournaments are beginning to be more strict against ledgecamping so be careful of that.
Gimping a good snake is really hard. A lot of snakes will wait too long to use the cypher in which case its pretty easy to call where they are going to be making a really easy edge game. If you happen to be in a good position to edgegaurd him generally be ready to attack somewhat above him as his cypher will bring him up. Better snakes will jump often even away from you then cypher right away. This will cause them to go vertical faster then pit can cover. A couple things you can do about this you can shoot a slightly charged arrow that will knock him out of the cypher, I believe 7 damage is all you need to hit out of his heavy armor. Also because they are trying to just go higher then you can guard sometimes snakes will actually go off the top of the map doing this. Cyphering off the top of the map won't kill them but if you hit them with an arrow outside the kill zone they will die.
Also on gimping snake has a fairly low horizontal movement speed. This means you can basically stay under him and juggle him to some extent. When landing against someone staying under him his best options are generally bair, airdodge or pull a grenade. bair comes out really fast and hits hard but can only attack behind so if you space appropiately its not too dangerous. Airdodge will leave them vulnerable upon landing for a couple frames but is a very common reaction. Grenade is probably the more annoying option using multiple hits will most likely blow you both up except for the dilema he is very heavy so it hurts you more relatively.
On the topic of grenades those are probably why snake is such a threat to pit. Snake is really heavy with more kill power then pit so trading damage favors him. Also the first hit of multi hit attacks set off a grenade. This is normally a pain because you need your kill smash refreshed to kill snake at a reasonable percent but if he pulls a grenade the first part of your fsmash will set it off dealing damage to both of you (possible for it just to hurt you if he shields but thats only if you didn't space your fsmash to avoid hitting a drop grenade) also this depletes your fsmash.
Controller port 4 helps deal with grenades but mostly only for grabbing. Just thought I should note that.
Generally for spacing I find if you space to avoid his ftilt works the best. Over 100% keep an eye out for his uptilt especially if he keeps it refreshed it hits very hard and has a lot of range.
A few of his moves are only really effective against bad di. You can generally di out of his dair, nair and jab combo.
Overall I do not like the matchup at all its playable and easy against a mediocre snake but against a strong snake I'd say 60:40 snake and call that optimistic.
I'd recommend deedee against him if your still trying to decide although that match controller port matters way too much for my liking.
edit: oops that wasn't meant to be so long.
