I bought this as a travel shaving bowl. The ones with the screw-top lids get easily stuck shut, and the metal is so thin it bends out of shape. You can get a plastic lid that fts nicely over the top of this bowl, making it perfect for travel.
I use one of the 3.5" Royal Shave ceramic bowls at home, and I've never found it to be too small. This one is not as deep, but you can easily put soap in the bottom and use your brush to create lather. I personally don't need anything bigger.
The only comment I'd make is that the total diameter of this bowl including the metal rim is 3.75 inches, not 3.5 inches. This is important if you want to fit it in a 3.5" medicine cabinet (it won't quite fit) or if you need a plastic lid (which fortunately come in 3.75" size, just don't order the 3.5" lids expecting it to fit).
Otherwise, this is a very high-quality item that should serve me well for a long time.