I visited USH the past two days. Crowds on Friday (without Grinchmas) were much lighter, as expected. For APs and/or those who don't care about Grinchmas, but want to see the new Magic of Christmas show at WWoHP, you should go on a non-Grinchmas day. On Friday night, there were no lines to get into Hogsmeade. No crowds to fight through. I showed up 10 minutes before the second showing and found a great viewing spot. And we weren't packed like sardines either. After the second show ended, I stayed for the third show and just moved back to a spot where I could hold my phone up and not block anyone's view. No one was ushered out after the second show--which I'm guessing they may do during Grinchmas and weekends. It was so un-crowded, that guests were able to walk into the viewing area *after* the third show already started.
Of course--as seen in the pics/video on social media--Saturday was a much, much different story. I didn't bother trying to wait in that line. I was very happy with my experience a mere 24 hours before.