Im almost done downloading, I was looking at the different character types and I was wondering, whats better, the Bow or the Gun? Id like to play as the Bow but idk if the gun is any better

Bow. Do not, under any circumstance choose a gun. Basically, there are 2 "upgraded" gun mercs that you can eventually get, and BOTH of them are MUCH better then the main. So yeah. Gun builds are primarily going to focus on stun/pressure, so if you want a stun/pressure build I'd suggest a cannon main.

Bow mains are strong, though they don't start to REALLY shine until level 100 (special main only bow that does STUPID damage).

Bow mains are going to build around PvP. If you don't plan on PvP'ing bow may not be the best choice for you, as silence has limited use outside of PvP.

These are the mains you should avoid at all cost:

Gun
Sword

These are the mains that are decent, but not considered top tier:

Spear
Bow
Cannon

These are the mains that are considered top tier at the moment(meta):

Axe
Staff

Obviously, if you're just going to PvE, and you don't want to be "uber elite" then it doesn't matter. Pick whatever you want. But I would still advise against gun over all others.

How did you determine these 'tiers'

I play as a Cannoneer and I haven't had any problem.

I said meta. This is the current meta game, and I didn't say you would have a "problem" with cannons. The information is a combination of current Division 1's and reading a lot on the forums. It's also based on a lot of analysis done by sites like MyAO. Cannon mains are better than artillery mercs, which makes them a viable main. Assuming of course you were going to build an arti into your build anyway.

I've just never seen a tier ranking of the classes, my friend is getting shitkicked as a staff weilder... but maybe it's because PVE

And yet I'm a staff wielder and kicking shit. I think it just depends on your build/style. A main is just one merc on a team of 9, so it's never going to be the end all be all. But my basis of analysis is by comparing the power of the merc version of each main and how much MORE effective the main is. In this way, you see what the real advantage of choosing it is a main instead of just picking up the merc version.

Spartan > or = LK > Swordsman > Sword Main (stat distribution for main is actually WORSE for a tank)

Jannisary > or = Inventor > Gunner = Gunner main

A cannon MAIN has more hp and more defense then an artillery main, so it's considered a viable pick for a build that would already have an arti in it. HOWEVER, the current meta-game focuses on powerhouse melee builds that utilize a prophet and an oracle (concentrate + seth's will). Therefore, a secondary healer that has a powerful AoE that can shrug off any AoE (staff m) and a very tanky axe user that has exceptional AP gain and freezing axe, are considered "top picks".

If I had to pick one main as being the #1 pick it would be Axe. But staff is gaining A LOT of support, although we'll see how that changes once rainmaker & the new alternate main classes are introduced.