The big bugbear with self-publishing is that you have to be your own publicist and distributor and that can be time-consuming. Lightning Source does give you the option of linking to Ingrams. This does mean that you have to offer a substantial discount, but this can easily be achieved by sensible pricing.
Publicity is a little more difficult and it does require your own effort. Book Promote do a very good service for £396. You have to weigh up your time again that cost and also remember that they have same expertise and same contacts that you don’t have. Then, you also need to programme in your own activities. They do need space, time and focus. Interestingly though, of course, you need to do this even if you are published by a mainstream publisher. And since you make a bigger profit margin on the book when you’ve published it yourself ….