Well, I got TWO classes, so why not?
Flame Wizard (magician knight of cygnus)
Yays (Advantages)
-Flame Pillar is extremely overpowered (Wee), so that's fast leveling, equaling a higher level blessing on my main, which will lead it to level faster, which is a higher level blessing for the wizard.
-Fire Curtain is AWESOME.
-I'm a Pyromaniac (LoL?)
-6 AP/level and being a Knight is highly appealing
-Free medals. They may not be 1/1/1/1, but they are something you can work with
-A MASSIVE HORDE of Cygnus-exclusive quests, which contribute a TON towards getting the 800 quest medal (<3333)
-Some 3rd job mage skills are in my second job. Well, all I know of currently is my Magic Booster :X
Nays (Disadvantages)
-Being pure fire is REALLY bad, especially if we have to fight something fire strong. I'm not sure about Fire Demon or anything, though.
-There's a slight "bandwagon" of Flame Wizards, due to their pure awesomeness.
-Flame Sprite sometimes causes unnecesary hate against nearby mobs
-Our fire arrow may be a visual roller coaster, but it's nerfed
-No poison = No death teddies D: Least we have C-2

-We cap at 120, so after that, we either just mass Jyakumu (Zakum) with some Koreans, or just pointlessly solo when I'm bored, or just solo Mureung Gym until I finally get that Black Belt, OR finish up any quests that I haven't done already, with the exception of Blackbull's new house (The one with that stupid deed), the Nependeath Juice quest and Arwen's Glass Shoe (Special dissaprovement for this - Fire Boars are FIRE-BASED = half damage with attacks = wtp?)
Gunslinger
Yays
-We are FUN
-I get to fill stuff full of lead

-Guns are left-handed weapons. Being a lefty, this is awesome
-Awesome tactical skills that, along with Sharp Eyes are beautiful and you will - I guarantee you - Fap to.
-Elemental attacks + Element amp + Summons that dont need rocks + Skill Buffs for those summons F-T-W.
-Homing is too awesome to describe in words. High raw damage PLUS that little Beacon of heaven is oh, so sweet. Adv. Homing only makes it better with a +% increased damage taken on that target.
-THE highest singletarget DPM in the game
-Do what you want cause a pirate be free, you are a pirate! I am a pirate, and I resemble one more thoroughly with pistols and awesome clothes!
-We're not buff whores, we're ATTACKERS ALL THE WAY

-Dash, Wings and Withdraw are all highly tactical ways to get away from mobs and are sweet. Plus getting on the hackershack in Henesys Market is fun.
-invis shot has a vertical range. Awesome, no?
-Thanks to our dex, we are one of the most accurate classes in the game. Heck, I could already hit D.Roys (~lvl73) at 33. Isn't that fun?
Nays
-Crap damage initially. Mastery GREATLY improves this and Invis Shot gives us a new edge, along with Triple Fire setting the new standard for non-crit damage :3
-Gun whacking is useless and should go away
-Imo, until you max mastery and begin working on invis shot, unless your gear is GODLIKE, or if your getting TWs in CPQ Or if your leeching, leveling is semi-hellish
-Dex stuff is expensive, and seeing as it's our main attack.. Yeah.
-Battleship DOES break down, and considering the minor-degree lag in KMS, if I ever go to a boss and use Battleship, doing the Dismounting tactic to downright avoid damage is difficult.
That's all I could come up with atm