I've just finished this book (reading since just after Christmas) Personally I didn't enjoy it at all. Having previously binge read the other Strike books and throughly enjoyed them, I was very disappointed with The Ink Black Heart.
There's far to many characters, Strikes stump is mentioned to much, there's far to much unnecessary swearing(I don't know whether JK thinks folk swear all the time or what!) and as for the 'gaming' conversations I ended up skipping most of them. I most certainly won't be rushing out to buy the next one!