I just joined, so sorry for bringing up a dead thread so long since you first posted. Yes, I have been using MoodleBox on a Pi3A+. It works great for a few users. So far no problems. Takes a bit longer to start up, but other than that its great. Due to the ram limitations there may be a limit on how many users you can have active at one time. i Have not tested that beyond 4 users, so I can't speak to more users.