I'm sure you already know the following stuff and I'm only telling it to those who don't and think this is THE great idea...
1) If you're subscribed to a mailing list (any!), you can't use an autoreply. Well, you can, but you will be fired from your job, you'll be killed by the list manager and burned by the other list users. (Think: Ping-Pong.)
2) An autoreply rule in Entourage doesn't do you any good if you turn your computer off. (I had customers who didn't think of that. They still think the Internet is *magick*.)
3) Autoreplies are basically a turnoff if you get them. Rather *tell* the important people you know that you'll be out of the office for x days/weeks once in one E-Mail. If this is for customer's mails, just either let your server forward the mails to your vice. Or do so yourself with a rule in Entourage.
4) Test your settings, if you have to use them, by sending a mail to yourself.
I hope everybody who knows this already agrees that they are important things to know and consider before installing such a rule.
Mac user since 1987. Running Mac OS X 10.9 "Mavericks" on a MacBook Pro Retina 13" & an iMac 27" and whatever's newest for my iPhone 5, HTC One, iPad mini and AppleTV 3.