well.....I'm writing this message at the
Air Canada Maple Leaf Lounge at YYZ's US Departures section.
I presented my papers to the immigration officer. We chatted and then he asked me to go to secondary inspection to get "processed". I had no idea what to expect...but sure enough, the officer asked: why do you have only one document. You should bring both of them.
But he really nice and processed my papers in a jiffy with a big smile.
All in all, the experience was pleasant and nothing to report. I've seen and heard that entering the US on an AP could be a hassle...But my fist experience is extremely smooth...heck it was better than entering the US as a Canadian visitor.