I had them re-direct my mail, but that was within Canada. It took about 10 days for it to actually kick in, but it was great after that and gave me the time I needed to change my address with my contacts.
Mine was a permanent move to the USA, but cant see why they would care if the move was only temp. as it is not free, they charge you for the service. can't recall what it was, something like $40 for 6 months. Could be more or less and that was back in 2004. Im sure it states the $$ on their website. As far as I know I received all my mail, and was in great shape!
Not completely on topic, but the guy at the post office told me that in Canada when they redirect your mail they do not inform the sender that your address has changed. However in the USA when they redirect your mail, the sender is notified of the change in your address. This is consistent with my experiences in redirecting mail in both countries. I'm not entirely sure which I like better.
Probably the Cdn system! Thinking more along the lines if you didn't want someone to know that u moved! Like an Abusive ex spouse, etc! IS that an option on the USA system (NOT notifying the sender)