There’s nothing awful or offensive about this message, but it’s also not very good. Yes, it provides the courtesy of letting the sender nominally know that you’re going to be slower than usual to respond. That’s nice. The problem is in this bit: “may be slow to respond to email.” Another popular variation: “might be slower than usual to respond.”
A good out-of-office email reply incorporates the following elements: The exact dates of your time off — If you are simply re-activating the message you used Typos — Your out-of-office message could go to anyone, from your manager to your top client. Avoid embarrassment by proofreading it carefully.It is also a good time to start doing daily good deeds. Happy holidays. “May the arrival of Christmas fill your heart with joy when you feel that by sharing with your loved ones an atmosphere of love and peace reigns because each of you carries God in your hearts.”

Same. There are a few people that are regularly in charge of things I need from them, but are part time. The vast majority of our office is full time. I have no idea when they’ll get back to me, or if I should email someone else. If I saw an OOO message every time they were gonna be gone Th-Fri, I would learn their schedule faster, and hopefully have the most up to date info about “oh, they changed their schedule due to Memorial Day, I can email them and get a response quicker this week” or whatever the issue is.
If you are checking emails while you’re out and are responding slower than normal, state that, suggests Jill Gugino Panté, director of the Lerner Career Services Center at the University of Delaware. “If you don’t have access to email and can’t return messages, state that as well,” she says. “The clearer you are in your messaging, the better.”