The Bagehot column in the Economist gets it about right:

It is true, or seems to be, that Mr Brown is maniacally ambitious but politically timid. He is intellectually curious but cripplingly indecisive. Witness the barrage of procrastinating policy reviews that he unleashes in every speech; unsurprisingly, more were set up this week, after the tragicomic loss of two doomsday discs by the revenue and customs service (HMRC). It is true, as the uncharitable gave warning, that Mr Brown copes badly with criticism—so badly, it turns out, that he sometimes shakes with pain and rage. He appoints supposedly independent ministers, then bullies them into line-toeing submission. He shies from blame when it is due and sucks up credit when it is not.

Unfortunately, the gristle and the guts—the ugly secrets of the Brown abattoir—have been gruesomely displayed for all to see. During the non-election fiasco in October, the country witnessed the low political calculation and fake ecumenicism, the shallow bombast and obfuscation, the indecision and ultimately the cowardice. In the first days of the Northern Rock crisis, it saw—or rather didn’t see—Mr Brown hide behind the sofa that he kept in Number 10 when Tony Blair left, just as he kept the uncollegial approach to government associated with it. Those who thought he could shuffle off his old skin when he realised his prime-ministerial dream, or at least that his psychological tics would not warp his tenure, seem to have been wrong. For Mr Brown, perhaps personality is destiny after all.