I also go with the mask under the hood. Sometimes it folds my ears a bit, but with a little adjusting this is no problem. To add to what others have said, it is a little added security that the mask won't (can't) go far next time some bozo kicks you in the face...
, I wear my mask under my hood. I find my hoods tend to trap exhaust air, even with holes punched into the hood to release it. The swelling of the hood starts pulling the mask strap tight, causing flooding issues.