I've read many of Iris Murdoch's novels, and I have to say that this is one of my favourites (on a par with 'The Bell'). It contains a host of typical Murdoch characters (the wayward and quite frankly bonkers woman, the homosexual couple, the intellectuals) but is in parts ruder and more coarse than various of her other books. I frequently found myself with an overwhelming urge to interrupt whoever else was in the room in order to read sections aloud; parts are pretty amusing.
As with some of her other novels, there are bits which seem odd or rather implausible. Hardened Murdoch fans should not be put off! If you haven't read any Murdoch before, this may not be the place to start (I would recommend 'The Bell', personally) but having said that, the writing is absolutely incredible, so rich and original, and I'm sure you'd enjoy it regardless. It is not a short novel, but there is not necessarily a positive correlation between the number of pages and time taken to complete - I tore through it simply because it's so unbelievably engrossing.