This was the first Christopher Brookmyre I read, though I have since read several more. In doing so I found that although they were all enjoyable, none were anything like Be My Enemy. In general I would categorise Brookmyre's work as satirical, witty thrillers, with clever plots and characters that are believable, if a little extreme. Be My Enemy is full-on farce in the vein of Tom Sharpe, with a few political rants thrown in. The plot is ridiculous, the characters often react to events in a non-believable way and much of the humour is based on shock value.
Having no pre-conceptions about what the author was trying to achieve I was happy to go along with this and had a great laugh along the way. I think the reason this book has had a lot of low ratings is that people read it having read other Brookmyres first and were expecting it to be something it's not.