For me the difference between him and Courtois is that he seems a bit comfortable with the ball at his feet compared to Courtois. He occasionally tries beaten a player rushing towards him.
Secondly I don't see him having weakness so far. Yes he has mistakes but mistakes can be corrected over time weakness can't really. As for Courtois, the opposite has a weakness of getting to ground balls quickly but little to non mistakes. Thats how he is able to concede three low played shots goal, two of which go through his legs by messi last season. I would still prefer we try to keep Courtois after all based on the last world cup, he is the best keeper on the planet.
If we should sell it should be above $60m