I played the first installment years ago and liked it. Returning to the franchise was great and the second one is naturally even better in basically every regard. Biggest difference I probably visuals and a new story. Also, Chosen seem to be a great addition as they bring additional tension to the campaign. I decided against Ironman mode and was scumsaving like a boss :) Thoroughly enjoyed the game.
Only minus I would see is that it's not that easy to grasp every mechanic the game offers especially if you hopping into expanded version of the game for the first time.
This game is not for everyone but I you like tactical combat there is hardly a better alternative.