What I understand is consumer graphics cards are all about processing for many frames per second. Image quality is secondary. Quadros are the opposite. As workstation cards, they don't have to pump out high framerates, but image quality is everything.
From a practical standpoint, you'd want a quality monitor to make a Quadro worthwhile. If you use a cheap gaming oriented monitor then you defeat the purpose of using the workstation card. Quadros can cost a lot, since they are aimed at professional use. Just as new generations of consumer cards come out, so do new Quadros. So there are many models out there, from entry level to top of the line, just like with consumer cards.