Well, yes and no.
I generally use the A-F grades since it gets me ready for later in homeschooling, but since we teach to mastery, the kids usually get A's. Is that really grading? Depends on your outlook....
In a classroom environment, kids are graded based on a scale: A and B are above average achievers, C is an average achiever, and D and F are below-average achievers. In a class full or 20-30 students, how can a teacher determine mastery and still have time for crowd control and the introduction of new topics? I shudder at the thought! Thus, a grading scale is quite necessary (although not always an accurate measure of a child's learning).
However, in our homeschool, the kidlets are not generally asked to do move on until they have the current stage mastered, so should they really be graded the same way? No, not in my opinion. So, my kids get "graded" on effort. If my kids are doing great, and they are mastering everything I throw at them, they deserve an A. But last year, we had some attitude problems, and in one particular subject, my eldest gave me a lot of trouble, so she got a B. Harsh? Well, here's how I came by my decision (it wasn't easy): She was presented the information, she was reminded how to tackle the subject, and she still could not get over herself long enough to do it properly. We met all of her personalities during that season! There was Whining Wendy, Yelling Yolinda, Grumbling Geraldine, and Disrespectful Dina. She repeatedly did not do exactly as directed and, therefore, made frequent errors. When she followed the directions as they were given and executed the assignment as directed, she could master it. Hence, a B.
So, yes, around here the kids get grades, but their grades are a different kettle of fish than their publicly-schooled amigos.