My favorite is Knokka. Half-human, half mechanical dinosuar, how is that not awesome?
Beast of a tank, too.
Nella - Love her Janus mask shoulder pads. She seems to have the most flexible skillset, pretty useful.
Frinz - Seems like a stereotypical dwarf, accent and all. Inexplicably has access to better technology but doesn't share it with anyone. I don't personally like him all that much.
Leck Lorus - I can't help but see him as a cross between Thresh and Sona from League of Legends (not necessarily bad, he looks awesome). I built to make his fear instant cast, it makes a nice reliable emergency interrupt.
Bo Lahm - Kinda stereotypical big dumb ogre, but I like his bone club with the daggers through it. He seems a far inferior tank to Knokka though. I'm kinda curious how he would do in a damage role, but I haven't had the chance to try it yet.
Denzil - I like the rat peeking out of his top hat. Seems to bring solid damage and utility.
Wendaroo - Seems to have the best potential healing, and the buff/debuff transfers is a neat mechanic. The character just doesn't "click" with me for some reason. Maybe it's because she's always angry and ready to tear people apart but is actually a healer with no damage skills, lol.
Motcha - I like the fact that the orc in the game is not a standard axe-wielding fighter. I've found his heal-reversal ability to be absolutely amazing. It makes me wonder how effective a party with both healers would be.
Loving the game so far. I'm about 15 hours in, exploring Act 2. The party I've been using is Knokka, Nella, Leck Lorus, and Motcha.