JL,
Don't get the 20-gauge. I recently cheaped out on a kitchen remodel and bought the "thinner" gauge stainless sink. It is really noticeable:
1. I makes noises when hot/cold water hits it.
2. The bottom buckles a little bit sometimes when full of water or heavy dishes.
Get the slightly thicker one.
Regardless of gauge of stainless, it'll scratch all the same.
We got one of HD's fake "granite" sinks for another remodel and they are fantastic. They are sturdy, quiet, and look good. However, they can stain with tomato sauce type stuff so be careful. You can kind of scour them out, however. Good luck.