We have taken our kids out many many times. My son was gone for a month in both JK and SK, and he is now in Grade 5, and an A/B student. Now both kids normally miss about 8 days, and every teacher we have had, has been great!!
His grade 3 teacher did kind of grumble, about getting stuff done, BUT said now she had the whole unit done and didn't have to worry about it on the XMas break. His Grade 4 teacher, gave him no extra work, just said have a great time.
As long as my children continue to do well, we will go.....