I really wanted a set of vintage tupperware measuring cups, you know the kind with the 2/3 cup, and the 3/4 cup measures that stack. My boss found me a set and I'm thrilled. I have a whole bunch of different measuring cups, but these are my favorites. I trust the measurements done with them. I have two sets of very similar stainless steel cups and noticed that one has slightly larger measures than the other. I was getting inconsistent oatmeal in the morning, sometimes dry (like I like it) and sometimes wet, and I started comparing cups and realized that the cheap set that looked like the better set was a larger measure!
When I see vintage tupperware in good condition in a thrift store, I buy it, if it's something I need. It seems to survive the dishwasher just fine.