I needed to put a short pause into an AppleScript I was writing. I first used a delay 10 statement to wait 10 seconds. I noticed, however, that processor utilization went up to near 100% for the 10 seconds. I switched to a do shell script "sleep 10" statement, and processor utilization remained virtually unchanged during the sleep period.
Based on this observation, I'll be using the latter statement above, when needed, to make my AppleScripts more utilization friendly and cooperative.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20021125061100716