An incredibly dull story somehow stretched out into a novel.
There was occasionally a witty line which reminded me of Douglas Adams and at which I actually laughed aloud, but this only happened about four times in the entire book.
The villains are un-threatening, the characters uninteresting for the most part (and the Doctor and Amy are essentially minor characters in this story, which is maybe a good thing since they were so wooden and out of character), the conclusion unsatisfying and there are numerous plot holes and things which barely make any sense at all. There are several problems that the Doctor should have been able to solve very easily, but apparently was unable to for no discernible reason, and there were allusions to some vague multiverse-wide threat. Had the danger been better described than ‘bad thing is bad if we don’t do this thing here’, it might have actually added a bit of tension, which the story sorely lacked.
There were also parts which were clearly meant to pack an emotional punch, but just fell completely flat.
It might be to the tastes of some, but I certainly would not recommend it. It’s definitely one of the worst Doctor Who stories I’ve ever experienced. Apparently this is not so much an extension of the Doctor Who universe, but of Michael Moorcock’s own, and so I am going to ignore that it ever pretended to be anything else.