I thought Amalur was great fun and I liked the premise and the way it played out. Avoiding spoilers, the premise is essentially that everyone's destiny is fixed, fateweavers can see fates and know when and how people are destined to die, but you're brought back to life by a gnomish invention at the beginning of the game and have no fate, allowing you to effectively screw with events and change everyone's fate. You learn more as the game goes on, if you care to read the dialog and stuff. At first you only have theories (what I said is from the beginning of the game).
It does feel kind of like a single player mmo, but not to the extent that borderlands 2 does. A more apt comparison would be skyrim with non-shit plots and non-procedural sidequests, you're more godlike than a Bethesda protagonist, and your money goes to EA, if that's a problem.
I didn't buy the DLC and played it on 360, so I don't know how good the pc version or the dlc is. I did stop playing and come back to it later several times, but I do that with any very long game. (For comparison I quit borderlands 2 with 2 characters around level 35 and never finished it)
I will note that after a certain tough battle more than halfway through I found that I could faceroll almost everything, but to me becoming the most powerful being on the planet felt realistic to the game's setting and backstory/plot concerning your character - Unlike what happens as you level up in Skyrim, for example (which feels doubly unrealistic).