I own a catacomb, and regularly play medusa at a friend of mine's house. With having to make a decision, I would pick medusa over catacomb by a little. Game play is challenging on both, artwork is great on both, rules are good.
But I think the bagatelle while well done does tend to break up the flow of the game. Especially when you have multiple people playing. It tends to throw them off especially if they are not that familiar on how it plays.