About the only things I concern myself with in regards to NVidia cards, is as follows:
1) Is the video RAM the correct speed to allow the GPU full speed access? (Cheaper cards usually skimp here)
2) Does the GPU have a good heat sink and fan? (Another are where cheap cards skimp)
3) Does the RAM have good heat sinks? (Cheapos skimp here too)
4) Is the video signal driver high quality? This one is tough. Cheap cards use low end video signal drivers which cause low light conditions in the image and/or fuzziness. If the card has a SVGA out connector, you can pretty much bet the video signal driver is a good one, but not always.
Another area where cheapos skimp and is impossible to know until you have the card in your hands are the number of layers in the PCB. This effects signal/video quality, but not to the degree the actual video driver part does. I believe the 8 layers is a good sign, 6 is okay, and 4 is bad. You can count the number of layers by looking at the edge of the PCB with a magnifying glass (well, I need a magnifying glass).