Peter Ackroyd's name on a title page is a sure recommendation for me. I've read others in his "brief lives" series, and enjoyed them all. What struck me about this one is that (as opposed to Chaucer or Shakespeare) there is a lot known about his 19th-century subject and (as opposed to Poe, who died at 40), Collins had a relatively long and very productive life to cram into 200 pages or so.
It didn't feel crammed, although there wasn't room for the kind of literary analysis that one would expect in a longer, academic biography. I think Ackroyd successfully identified the major themes and traits of Collins' best-known novels, and made connections between all of the writing and the life where that connection is evident. I got a clear picture both of Collins the author and Collins the man, and a reasonably good sense of the major relationships in his life (including those with his two concurrent mistresses!) The strong and lengthy friendship with Dickens got fair play here, but I imagine there is much more detail in Ackroyd's very decidedly not brief biography of Dickens which is sitting on my "to be read" shelf.
As I am reading through Collins in a rather haphazard way, this little book provides very useful context and I'm happy to have it on my shelf.