Just purchased from GAME.
Will let you all know what i think. 
Mine arrived today (xbox)
There's an annoying texture load and resolution issue (which i thought had been patched) and some areas look very grey/brown/generally washed out. The game world does however have variety and some nice touches.
Gameplay-wise its a mixed bag. Its much more frantic than lets say Battlefield, to the point at which you can easily lose track of what's going on and which objectives require completion. Being objectives based, its not just about blowing crap out of other players. This is especially true about offline play which requires your human touch (rather than your friendly AI bots) to get things done; you cant just stand back (or camp!). There are many ways you can gain XP and help your team progress though, so if you're fed up defending a point you can either escort a valuable player or capture a tactical position.
Your movement doesnt appear to flow brilliantly to warrant the fast paced gameplay however, it feels almost clunky. I'm hoping that's something I can get used to (its certainly not Modern Warfare-smooth), or maybe it will be patched.
For the most part the SMART movement system works well but occasionally its unclear which walls/ledges you can climb and which you cant; it would have been nice to make the surroundings compliment this (as Mirrors Edge did, by making the world generally high contrast, bright and hinting at key obstacles to manoeuvre over/around/onto etc). Instead you're often presented with many dark areas and few clues.
On the other hand there's plenty to do offline as long as you like set-pieces. The story doesnt really facilitate much other than to give reason to blast sh!t out of eachother and progress from one side of a map to another within 20 minutes. Offline play is essentially online multiplayer matches with bots (the AI however isnt great).
I havent played online yet so cant comment, although I see the 'offline' campaign allows friends to join by default. Alternatively you can play campaign with anyone (up to 8 players) or restrict it to solo play only.
The unlocks, character and weapon customisation is where Brink really shines though. XP will earn you clothes, accessories, weapon mods and skill unlocks, I spent ages changing stuff
Overall I think I'll get used to the movement and making the most of the SMART system to manipulate the game world the best I can, and I probably shouldn't moan about the objectives not being clear as I've only played it for about 2 hours if that.
In summary I'd suggest that the Modern Warfare crowd wont like it. The Battlefield crowd might, however the gameplay is faster paced so takes some getting used to.
Story = 5/10 (doesnt do a lot! Although it does provide an interesting game world)
Graphics = 6/10 (due to texture issues - this may be patched out later)
Sound = 7/10 (average)
gameplay = 7/10 (clunky in places, sometimes objectives not clear)
replay value = 10/10 (as long as you dont mind the issues above. Lots of unlocks, mods, levelling up etc)
7.5/10 overall
