36 hours for me. I can tell you exactly when it tanked -- approximately 2AM ET on the 17th. I was happily matching a few hours earlier, but around 2AM the process completely slowed to a crawl. I'm guessing Europe was waking up and those 19 countries starting subscribing and matching.
It's really bad - the worst outage I've seen so far, and I've been using it since Day One (US customer). I've already called them and also put in Apple feedback. I figure it couldn't hurt plus I just wanted it documented that I'm affecting by this issue, right now.