Having done both their first runs I really preferred the shotgun, Magnum and flamethrower over the grenade launcher, SMG and Spark Shot.
The shotgun and Magnum are so damn handy for one-shotting and the flamethrower is useful against the ivy zombies. I ran out of flame rounds at the end and got my head chomped doing Claire's run.
I got a B, by the way. Just couldn't get done in under five hours.