Although it's resulted in some books I've absolutely hated, I like the fact that you never quite know what you're going to get with an Iain Banks novel. In the case of Transition what you get is a touch of his Iain M Banks output - in fact apparently in America this novel is published with the middle initial that denotes it's one of his Sci-Fi books rather than a more literary effort. Taking place across multiple quantum universes, it's narrated by various members of The Concern, an organisation that carries out missions in this multiverse, and whose operatives can "transition" from one reality to another by "flitting" into the body of someone else. Much of the novel is taken up with building this fictional universe and it's one of those where as you approach the end you start to realise very little has actually happened. Not, in my opinion, in a bad way, although I can see how people could dislike it.
There's a conspiracy story involving the high-ups of The Concern but largely this is a venue for Banks to muse philosophically and on a few political points like terrorism, religious intolerance (most of the parallel universes feature Judeo-Islamic earths where Christian extremists are blowing themselves up,) torture and the financial crisis (the unfairness of PLCs is a recurring gripe.) But he does it entertainingly and despite its meandering ways I enjoyed Transition.