We've had a high number of power outages this year, the worst lasted 9 hours. I didn't have a generator then and after the water drained I had many, many sps colonies that were completely out in the air others were just partialy covered. They all looked just fine after the power came back on, lots of slime but the corals were fine. I've found that digis and birdsnest don't fare as well and have die off. Like Steve said if you're exposing them for a water change make sure the new water isn't going to burn/stress them out.
The acro smell was pretty strong, I love the smell of acros in the morning, but there weren't any problems.