Finished the game last night and I was very impressed. I must say in the end I liked this game better than God of War 3 because it gave me some things that GOW 3 didn't, mostly the spectacular settings. The game is just gorgeous, the difference between artworks and actual game is minimal. I'm resistant to framerate troubles I guess, I didn't notice any problems to be honest.
I also loved Mercury Steam's solution for the QTE's - very unintrusive and more dynamic than they were before.
The ending was awesome and surprising, I hope they get to make a sequel.
What I didn't like was the trophy distribution. It's a rather long game, I finished it on "Normal", collected lots of gems (not all of them though), and after I'm done and otherwise very satisfied with the game, my Trophy count is a lousy 25%. I'll probably mop up a few more in a few weeks, but that's just not a good "end result" for a single player game.
The titan battle "homages" to SoTC were a bit too shameless in my book as well. They played nicely, but if you copy a great game so closely and without there being a need really, it leaves a bit of a sour taste for me personally.
Overall it's a great game though that ranks quite highly on my GOTY list and it definitely put Mercury Steam on the list of developers with lots of potential. It reminds me a bit of what Batman did for Rocksteady last year as far as image is concerned.