I don't know.
Between me and my friend we worked out that I'd play Lann and he'd grab Fiona, It's hard to say who deals the most DPS simply because manhandling gnolls is so easy, but if you get into it I've seen my friend block so many attacks while keeping an offense going in boss fights, while I have to back off and lose some DPS while trying to get out of the way and back to the boss at hand, he can continue his assault by just blocking and resuming his attacks.
This is only an observation from a low level player though, they both have their niches, I'd just go with whatever feels 'right' to you.










