Short version: This game COULD be awesome if it was given some huge updates. That being said there are so many things wrong with it that it makes me reconsider playing ANY Assassins Creed or Ubisoft game (and thats coming from a faithful, long-time, original fan of the series.)
Ill start with what I liked:
Visuals in most parts of the game are great. Most of the big, orchestral music is really nice. Raiding is awesome. Interesting storyline, (but if you know your Norse mythology you'll know they basically stole some pieces of the sagas and just mashed them together) .... Thats about it until they can make GIANT updates.
As for the cons (Ill try to make it short):
LOTS of glitches, conflicting controls (such as R1 is both light melee and assassinate), conflicting codes/ bad code writing (quests that wont let you overlap them, music that wont stop, icons that either dont show up or wont go away, collectibles that you cant collect, your "danger" sense that wont stop going off even if you're clearly alone, trying to loot a chest that requires TWO characters during a raid, but your crew just stands there watching you struggle, ect) and error screens. The skill menu makes 0 sense! You have multiple bows which have different skills and different arrow types, but you have to pause the fight to switch between them. I could keep going, but thats the short of it.
I find new glitches and errors everytime I play and Ive been playing pretty much every day since it was released a couple weeks ago. (70+ hours) IF this thing gets a full overhaul I might consider finishing it, but at this point its not only a waste of time and money, but patience as well.