Of all the Vorkosigan Saga, this is my favourite. It's full of twists and subplots and misunderstandings and fun, pretty much a slapstick romantic comedy with drama and intrigue! I know of people who have started reading Bujold with this book and been completely hooked, but there's a lot to be said for following the internal chronology of the series, which would give this book a lot more depth with the background characters.
Miles, despite his new vaunted role as Imperial Auditor, manages to really muck things up in his carefully planned strategy to win the affections of Ekaterin, now living in the capital on Barrayar. Added to this the inevitable galactisism of the planet, manifesting in gender changing, illicit baby growing and the possible effects of gene checkings, to keep Miles hopping, A Civil Campaign is an absolute riot.
Highly recommended, but possibly best read in order.