I, too, will hold myself back, as this is a touchy subject with me.
We only took our DD out of school once, when she was in 9th grade and she made us promise NEVER to do it again! In spite of the teachers' efforts and our DD efforts to make up the work, it turned out to be more than anyone bargained for. She suffered for weeks, if not months, to catch up.
I think it's crucial to the situation to factor in what grade your child is in. Some grades are easier to miss than others. I think the younger the child is, the easier it is. When you get into HS, it's very difficult.
But do allow me to vent one statement that I really can't take about this issue and that is when parents and sometimes even teachers say they're taking their child on an "educational" vacation. Hey, unless you're taking them to the Smithsonian, a museum, or the like AND that's what they're currently studying in school, I don't see where a trip to WDW or a cruise is an "educational" experience. Yes, they will learn certain things while on these vacations, but not necessarily what applies to them currently in their curriculum. So, it isn't going to help them with work they missed.