I did a few things like this from my time at VOW, Caboodle and the Post Office Shop. It is really more of a user preference thing than either selecting one over another.
What works best for your content - is it text or image intensive when it comes to your product listings, I often found if there was more image than text - a grid worked better, and vice versa if there was more text.
Also consider mobile - a list solution may be the best option on a smart phone and grid on a tablet.
The optimum solution in my opinion would be to allow the consumer/user to select their preferred layout. You could implement this as a checkbox/button that simply switches the css to display in either grid or list format.