I'm a big fan of McKeown.
He plays at least 25 minutes a game and is the top Dman for the Fronts. He had a great playoffs and was playing against Nick Ritchie for a large part of it, where overall he did really well against him. They had some real classic physical battles and McKeown got the better of him for the first 5 games or so and then seemed to wear down a bit as the playoffs went on (although that could be because Gill played only four Dmen). For most of the year he was very good, but did have a rough stretch about a month or two ago.
I really like how cerebral and calm he is. He is great positionally and really thinks the game out there. You never worry when he is on defence, which is rare at his age in the OHL. He needs to put on a bit more weight (who doesn't at 17), but I think he's going to be a real good player in the NHL. He reminds me a lot of Pysyk, with a bit more offense. I'd love for the Sabres to grab him mid-1st, but I know realistically it's unlikely. I think he's going to be a steal for someone at that position.
He was also nominated as top Dman in the entire league (along with 5 others).
And don't ask me about Watson, as it won't be as glowing, especially after his weak playoffs!