My choice is somewhat dependent upon my matchup. If it is a game I should win then I would most likely go with the highest floor (Cam). However, TB is playing against a Steeler D that is non-existent on Monday night in Tampa. There is no reason to believe that Fitz should slow down. He has the higher upside but has more risk as he has been prone to turnovers.
One other thing, If you don't have negative for turnovers then there is no reason not to play Fitz.
I'd go Cam. Fitz has had a great start to the season, but he's had great stretches before and has always come back to earth, yes weapons may be better than ever, and I think he's a top-10 at the moment, but Cam is a stud, and has played like it so far. Cam is a top-3 guy.