I haven't spent as much time with Fallen Earth as I would like to have, but so far I am enjoying the game. Ultimately it's the sandbox openness of the game that I really like, among a few other things. Alik on the MMO voices podcast said something to the effects of it's the feeling of being able to do anything you want without having to be lead by the hand from quest to quest.
But I do have one complaint, and that is the combat. I actually think the combat quite neat and can be fun if everything is running smoothly. I am experiencing a bit of frustration right now using the crossbow at close range because mobs have been warping some around my guy. The bigger problem is the clunky way to switch weapons. Instead of using a crossbow at close range I should be using a melee weapon, but's such a pain so switch weapons.
It's just a minor complaint and it's not enough to ruin the game for me.