I am not a collector of mugs but a user. For use, it is hard to do better than an Old Spice mug. Fits the puck and has a flat bottom. Sides not so tall so that you bang your fingers and brush handle when making lather. Sides high enough so that the lather does not over flow the mug. I prefer mugs to bowls as the loop handle provides for a secure grip. I keep my eyes open for any interesting mugs, or bowls, that have the correct shape. Hand made mugs from pottery shops or vintage mugs from flea markets and yard sales are a nice source for user mugs.