General

In terms of gameplay and fun, I personally would choose sair.
Also, just have strong link skills and get a strong character card set
That will siginificantly improve health for any class

I will say that it's entirely possible to be a sair that isn't squishy but it takes work. You need your kaiser and cannoneer links. You need your ra set and other gear to get defense up, and you need whalers potion. And with all these things you will not be tanky, however you won't be below average. It isn't worth it unless you know it's the class you want and you're willing to point all of your accounts resources in one direction for it. As far as character cards and other such benefits, there is no reason to have a corsair.

Corsair: pew pew pew
Cannoneer: KABOOM KABOOOM

@mvietp09: The issue is that Eight Legs Easton is as slow as Cannon Bazooka, if not slower, and broadside is weird with how the cannonballs bounce. Sairs also mostly boss with Headshot, which is around the same attack speed, if not slower, than Cannon Barrage. For all intents and purposes, Cannoneers are actually faster.

[quote=SnailPresident]@Ecarina:

All true except that with red sairs also received inventory expansion and master of swimming.
EDIT: Another minor correction. Sairs CAN use brain scrambler and easton while the glide effect on wings is active.

Cannoneers are the better class on paper. I've considered maining one several times.

Cannons have:
1. Tankier
2. Better dps
3. More lines per second
4. Easier to train
5. Fewer buffs
6. A higher range by default.
7. No need for bullets

Sairs have parrotargetting which offers nice precision for bossing but 99% of players would choose cannon over sair.[/quote]

This comparison is sort of similar to bowmaster vs crossbow man. Corsairs are primarily fast attackers whole Cannoneers hit harder and slower.

Go with Cannoneer

@Ecarina They gave those skills to the other 2 pirates in RED so it wouldn't screw up inventories when job changing.

@SnailPresident: Oh wait all pirates got the inventory expansion? I guess that explains why my sair had so many slots I didn't remember adding xD

@Ecarina:

All true except that with red sairs also received inventory expansion and master of swimming.
EDIT: Another minor correction. Sairs CAN use brain scrambler and easton while the glide effect on wings is active.

Cannoneers are the better class on paper. I've considered maining one several times.

Cannons have:
1. Tankier
2. Better dps
3. More lines per second
4. Easier to train
5. Fewer buffs
6. A higher range by default.
7. No need for bullets

Sairs have parrotargetting which offers nice precision for bossing but 99% of players would choose cannon over sair.

Cannoneers are tankier, have a longer range on their attacks, and have better mobility than sairs. Cannoneers also have a link skill and more storage space by default. We also don't have to waste use slots on bullets.
Sairs have the advantage of being a dex class, making them significantly easier to fund and using a gun as a weapon, which can be used on 2 other classes if you choose to train them as well. That's kind of it to be honest, I'm sure someone who actually mains a sair can tell you more, but I just got mine to lvl 200 and quit it.
Cannon Jump is basically a better version of Wings by the way. It shoots you into the air the same way, but it can also be used in the air, whereas Wings has to be used on the ground. Cannon Jump also allows you to use skills while you're using it, whereas Wings just makes you float down before you can use any other skills. If the cool falling animation is what you like about Wings, I can't say much about that, Cannoneers can use Cannon Jump and Monkey Push in order to have more mobility in the air but we don't have that fluttery cape thing.

Cannoneers can take quite a few hits, and they got reasonably high W. Def being a Str based class.
Personally I also enjoy 'neers a bit more than 'sairs.

STR vs DEX

Ha! ^

Cannoneers have HP raisin' link skill and hyper, so yah tankier.

Mechanics are "tankier" than both of them