I recently spoke with Dr Peter Higgins BVSC,MBA who is Media spokesman for Dogs NSW at the 2008 Sydney Retirement and Lifestyle Expo. He full endorsed live-in house sitting pet sitting or as a preferred kennels alternative. He said putting dogs in kennels can lead to behavioural problems. 
Here is a link to an article on Dog Stress reprinted by permission from author Dr Kristie: 
Is your Dog Stressed