If you've bought Stellaris and are wondering which expansions to get; I'd put MegaCorp lower down the list honestly. Utopia should absolutely be your first pick-up. If you've gotten that one though, and you find MegaCorp appealing? Go for it.

It's main addition is the MegaCorp Authority, which while not assymetrical enough in their playstyle for my liking, have a unique mechanic of building on other empires planets to provide benefits for both empires, which is a fun idea.

MegaChurches are a fun flavourful spin on that, and Criminal Enterprises are a bit... trickier to use, especially in Multiplayer (and in general are annoying to play against) but I've gotta be honest, since I started playing Stellaris I've wanted to make a knock-off Hutt Cartel so it was kinda perfect.

Other than that, a few new MegaStructures - none that are super amazing, though more stuff to build is always nice.

The casino thing though, I could do without. I miss the old caravaneers...