As you already know, stainless steel sinks vary by gauge of stainless. A thick one will cost a lot more. They also vary by the undercoat treatment, used to silence the clinky sound. There are also different grades of stainless. This can affect appearance and the ability to remain rust-free. This information is harder to come by.
You always pay more for Kohler. Not neessarily worth the money. There are many good name brands: Elkay/Dayton, etc. If you buy a cheap import, you don't know what's in the steel.