I think he's going to be either really good or really bad. I do not see him being an average Flacco/Dalto type QB. He's either going to be an absolute superstar or a total bum. Imagine Doug Flutie in today's kinder, gentler, defensively neutered league. That's the projection, IMO.
With that being the case, I'm not sure how I'd feel about the Browns taking him. A rookie could have a worse supporting cast than one featuring Josh Gordon to throw to and Joe Thomas protecting your back.
If I'm the Browns, I take Watkins, if he's there, pair him with Gordon and draft a QB with one of my other top 40 picks.