I use China for the adults and Corelle for the young ones. Under 2 gets plastic. I barely ever use plastic even during the week – and I don’t have a dishwasher, nor would I let my cleaning lady wash my dishes.
I do recall my husband telling me that at a shiur on Hilchus Shabbos the person giving the Shiur mentioned that officially it wasn’t so OK to use plastic since after you’re done using it – it becomes Muktza, however, since some food usually remains in the plate then it’s OK.