You pretty much know the main points
I was at Epcot yesterday and people lined up for the 1:30 set of Santa and Mrs Claus around 12:45pm. Maybe 10 families in line so not horrible, the line does grow with each set
The good thing about the DHS Santa is that you don't have to wait in line, with the pager system you can come back and only wait 10 to 15 minutes. The DHS Santa is in a beautiful room, I'm sure it would make for great pictures
Remember there's also a Santa at Disney Springs, same pager system