WitchDoctor-Love this so much Buccaneer-Hated at first but managed to solo much of the game and not that much companions! Musketeer and Swashbuckler-Both great for me.Soloed almost everything Privateer-Team work class.Ew.Too much companions and never liked since my main beta character was a privateer.
Swashbuckler~ EPIC! WitchDoctors~ AMAZING! Privateer~ Awesome Healer Musketeer~ Cool Buccaneer ~ Eh... it's great if you don't want to manage a lot of companions. At least you don't need to spend a lot on training tombs to upgrade your companions (I think by lvl 50, you'll have less than a page, but not sure).
Buccaneer-It's a Tank! Can take a lot of damage, and boost its companions to deal quick damage. It also has powers that enable it to travel all the way across the battlefield in a turn. It's powers that damage health also damage stats. Buccaneers tend to have low accuracy, however. It seems that this class is only as good as their powers can take them.
Musketeers-This class can damage enemies from far away while its other companions pick the enemies one by one. A Musketeer can lay down deadly traps to damage their enemies even before the enemy can touch them. Musketeers tend to have low health, and if their companions get taken out of the battle, he becomes very weak and defenseless.
Swashbuckler- This class can deal very high damage very quickly. This class has powers that can make them disappear and be immune to certain attacks. Swashbucklers can deal Damage-Over-Time powers while they are still dealing heavy damage. This class has very low health to balance out its power. This class has very low defenses, as well. If a Swashbuckler can get caught off guard, they can easily be taken down quickly. Their hiding powers can be negated by an AoE, like Old Scratches Increased Mojo.
Witch Doctor-This class is like the Musketeer and the Swashbuckler combined. It has range spells that deal heavy damage, and team boosts like their Juju powers. This class can also summon weak Henchmen as distractions. This class doesn't have a lot of health, and has very weak defenses.
Privateer-My favorite Class. This class gets the most companions, the most health, and the most defenses. This class has many powers to boost the moral of the rest of the crew. It has an incredible healing power, and can dodge like there's no tomorrow. As long as a Privateer can keep its companions alive, it can solo anything, easily. The only downside that I can think of is that this class has very bad hand-to-hand skills.