I watched the extended cut, and while Ben Affleck is an astute director (on the evidence of this and Gone Baby Gone), I'm not so convinced by his pulp-masquerading-as-serious-drama subject matter in either of his films so far.
Nor am I convinced by his choice of first his brother and now him in the lead roles for his films. Both seem like miscasting. I don't buy Affleck as the blue-collar bank robber. He seems to be trying too hard, or not hard enough, to inhabit his role. In contrast, the supporting cast is deftly chosen. John Hamm is a natural movie star, making gold of every scene he appears in, whilst Jeremy Renner is a natural for the role of psychopath, bringing the unsettling crazy effortlessly (I wonder how he'll handle the trad hero in M:I4). Pete Postlethwaite is particularly venomous in his penultimate role.
The extended cut seems overlong (25 minutes more than the theatrical) and too much time is spent on the unconvincing romantic subplot between Affleck and Rebecca Hall’s oblivious victim. The heist sequences show a natural confidence from Affleck the director, though, and I expect that at some point he will find material that allows him to break out into making a classic movie.