I like it much more than FF13, as the combat has been improved (it's actually challenging at times if you don't play on Easy Mode) and I actually really like the new character, Noel. There's also a LOT more to do. Most of the game is sidequests and exploration, unlike FF13 which only had sidequests for the later half and they weren't that great. The sidequests in 13-2 actually tell you stories and stuff, unlike 13's which were basically "go here, kill these things, retrieve item". I liked the story enough but the ending is... well, you'll see. Characterization is much better in this game, in my opinion, as even returning characters become more likeable than they previously were while not feeling out of character. Maybe this is considered a spoiler (early spoiler), but Hope comes back and he plays a big role but he is actually not an annoying little shit now and I actually liked him despite hating him in FF13.
I enjoyed 13 but that doesn't really mean much, though, I guess. Some people that enjoyed 13 actually hated 13-2 and some that hated 13 actually loved 13-2. It's weird.
Oh yeah, I would suggest that you pick up the Coliseum DLCs if you want REALLY challenging fights to do after you've actually finished the game. I really REALLY suggest them if you like classic Final Fantasy, because the Coliseum bosses are all from the classic FF games! Typhoon, Pupu, Gilgamesh, etc. The greatest part is that you can have them join your party!