What's there not to like here- There's Gerard Butler. There's lots of action. There's some so-so acting (hey Keanu's acting was so-so on Speed, and everyone still loved the movie, so yes, some movies can survive so-so acting). There's lots of variety: a little Indiana Jones, a little The Mummy, a WHOLE LOT OF CGI madness. There's quite a lot of style – Geoffrey Rush's ship and his clothes are a work of art!
It's one of those movies to watch when you've had a very tired day and just want to watch some crazy action without being too worried about the storyline. It's all in all surprisingly fun. Whenever I see professional critics pan a movie, I tend to want to see it for myself, and often, I find myself disagreeing with the pro critics. Watch it if you're looking for a fun movie.