My regular shop tends to have games a few days earlier...which is why I give them my money
I really like it so far. The story is very well presendet and immersive, Jason is NOT a silent protagonist, Vaas is tremendously cool as a villain because he´s so volatile, the weapons feel good and make sense...
If I had to say something negative it would be that the performance on the consoles is not as good as it should be. Apparently the 360 is tearing like mad at times and both versions have a sub-par framerate as far as I can tell.
Apart from that, it has the same samey structure all big Ubisoft Titles have, it tends to become repetitive, the game is, as AC3 was, a huge collectathon. Thankfully, the game tells you when you get a reward for something, you know exactly how many letters you have to find to get a weapon unlock, etc.
That said, gameplay is a lot of fun, the whole feeling of unfairness from 2 is gone as Enemies are not all-seeing and all-smelling. The game makes it very clear that it wants you to sneak but if you want to shot everything up, it lets you do that too, no problem, you just get more XP for silent close quarter-kills, kinda like Deus Ex HR did it.
The skill-system is a mixed bag at first, as is the crafting system. You start out with very limited carrying capabilities and you have to upgrade step by step. Though I´m 6 hrs in and I´ve maxed almost everything. The last tier of something is always unlocked by a hunting-quest that has you kill a special animal with a specific weapon.
Killing shit gives you XP which gives you Skillpoints. How many Skill-Tiers you have is dictated by the main story, so my advice is to do some main missions right away. They start off easy and tutorial-esque and after a while, you get the second tier with a lot of cool skills like special takedowns. Knife someone, then take his knife and throw it at another dude. Or arm his grenade and kick him into his buddies, stuff like that.
Lastly, the plants and syringes. There´s 5 types of plants (red, green, blue, white, yellow) from which you can craft...well, potions basically that let you breathe underwater, see enemies or animals, scare animals away or become fireproof, all kinds of things. Doing missions and challenges unlock more recipes. Pretty cool stuff, though you will spend a lot of time in the menu, mixing up your near-paranormal potions :D
All in all, I´m impressend and very pleased so far.