The biggest thing about Eve that people I've talked to don't like is that they can't 'fly their ship'. Eve is not a space flight simulator.
The biggest thing about Eve that no other game has is that the vast majority of the 'game' is player generated content, in effect. Nobody talks about how fun it was last night to grind that Guristas Extravaganza mission for the 1000th time. What they talk about is the 500 vs. 500 fleet battle in some system that resulted in 20 lost capital ships for one side or the other and the winners took sovereignity of the system when the smoke cleared.
Player organizations waging war on each other is the content. However, you can't have all ship pew-pewers to win wars and hold territory. In fact, that's actually a small part of it (time-wise, anyway). You have to have massive logistics and production... all done by players. Those 20 capital ships that were lost? All built by players. They arrived at the battlefield by players both flying them there and other players who have to fly other ships to the destination to open up jump points for the capitals to jump to (fly through enemy space to get there). Those 50 battleships that were lost? All built by players. To build all those things, you have to mine (or buy from someone who did) minerals from asteroids, minerals mined from moons (requires a station to do that), and your systems can only be 'yours' if you have sovereignity, which requires stations that must be set up and defended.
Yeah... Eve is complex. But, there are those of us who like complex games. It's not for everyone and "that's OK".
One thing that's really nice about Eve... I can play heavily for a day or two and then not play at all for a week or even longer and not have any withdrawal or even think about the game if I don't want to. The only thing really requiring a player to log in is if you make money in the game by running missions. If you have an industrialist, you can make money while not logged in (buy materials and sell your player-made goods on the market while you're offline). You also advance your character even when not logged in. So, when I went on vacation for 10 days over the recent holidays, I had zero withdrawal from the game, didn't log in a single time over those holidays, and didn't worry or really even think about the game at all. When I got back, I had more money than when I logged out before my vacation and a new skill almost completed so I had something new and shiny to play with when I logged in next. Plus, stuff that I had set up to build while I was gone was built and ready for me to use/sell.