Taken from PSO-world.

Figunner
Unique trait - Exclusive access to Double Sabers. Only class that has S rank on both Sabers and Dual Sabers.
Photon Art Distribution - Level 30 Weapon Skills, Level 20 Bullets, No Techniques
Requirements - Job Level 5 Hunter, Job Level 3 Ranger

Guntecher
Unique trait - Only class with S rank on Dual Pistols, Crossbows, and Machine Guns.
Photon Art Distribution - Level 10 Weapon Skills, Level 30 Bullets, Level 10 Techniques
Requirements - Job Level 5 Ranger, Job Level 3 Force

Wartecher
Unique trait - Closest option to a FOmar from PSO, with no unique weapons but midrange melee and technique capability.
Photon Art Distribution - Level 20 Weapon Skills, Level 10 Bullets, Level 20 Techniques
Requirements - Job Level 3 Hunter, Job Level 5 Force

Fortefighter
Unique trait - Only class that has S rank on Swords, Fists, Spears, Axes, Claws, and Dual Claws. Most S rank weapons of any class.
Photon Art Distribution - Level 30 Weapon Skills, Level 10 Bullets, No Techniques
Requirements - Job Level 10 Hunter

Fortegunner
Unique trait - Only class that has S rank on Rifles, Shotguns, Grenade Launchers, and Laser Cannons.
Photon Art Distribution - Level 10 Weapon Skills, Level 30 Bullets, No Techniques
Requirements - Job Level 10 Ranger

Fortecher
Unique trait - Exclusive access to Staves and Level 30 Techniques. Only class that has S rank on Bows, Cards, and Rods.
Photon Art Distribution - Level 1 Weapon Skills, Level 30 Bullets, Level 30 Techniques
Requirements - Job Level 10 Force

Protranser
Unique trait - Only class that lacks S rank weaponry, but also the only class that has specialized trap usage.
Photon Art Distribution - Level 30 Weapon Skills, Level 30 Bullets, No Techniques
Requirements - Job Level 5 Hunter, Job Level 5 Ranger, Job Level 5 Force
Edit: Job Bonuses
*Fortegunners, Fortefighters, and Fortechers enjoy a 20% reduction in PP cost for their Arts, Bullets, and Techs respectively.
*Protransers enjoy a 50% boosted crit rate.
*Fortegunners and Guntechers enjoy a 30% boosted crit rate.
*All expert jobs enjoy a 25% boosted regeneration on weapons that they are primary in use with. Example: Wartechers, Guntechers, and Fortechers all earn a 25% boosted PP regeneration with casting weapons.
*Certain races gain "prefered" stats when using certain jobs. These are on top of the class stat mods.
I myself am planning on Fortegunner and Protranser.