Ef has a lot of main characters and not just one, each chapter revolves around a different main character like suika said but later on some of them are continued even when you think that they don't have an ending they do, it's a little weird but it works, some of them have really good plots others are meh.
There is a lot of romance and you have ero-scenes that add something to the plot!! Prob the 1% of the vns out there where the sex makes sense and it's not there just for fan-service so yay for that
The chihiro's route is the best love story I've ever read by far, not your typical bs love story it was really well written.
The art is great and it's fully animated with a lot of cgs A LOT of them, 9/10 for me, btw eden* was good but a bit boring for me.