This is what drives me nuts about some Leaf fans. Fraser, if anything, blew game 6 for us (up to debate, considering the Leafs played for another minute or three, and replaced the injured player on the ice). They played game 7 and lost. That loss was on the Leafs, not Fraser. Get your head out of your Blue-painted a**.
The fact of the matter was the Leafs couldn't beat Gretzky, who's one player on a team of players. If you can't beat a player, then you can't beat him plus his entire team and thus the better team won.
On topic, I started watching the Leafs in the Cujo era, so I never really got a chance to watch Potvin. That being said, even though I never watched him, I think I'd choose Potvin from what I hear about him. I consider a couple things from what I remember about Cujo:
The way he ditched the Leafs, he showed a lack of class, especially with him saying something along the lines of "wanting to win a Cup..." as he walked out the door. Poetic justice that his career went nowhere afterwards.
Not to mention my heart would skip a beat every time Cujo either left the net or puck-handled. The first Leaf game I ever went to, Cujo went behind the net and passed directly to a St. Louis player, who scored a goal on Cujo's empty net. What NHL goalie puts the net into his own crease without looking first? I never got anxious watching Belfour go get a puck, which sealed the deal on my opinion of Cujo.