To comparison shop, the easiest way to do this is by doing it all online. You can go to certain sites such as consumer reports which makes it easy for you to compare a product with the same type of reviews.
You can see the same type of reviews for different products. For example, searching for a tablet, there is different reviews for things like display and ease of use or screen size. Then you can take the criteria that you like and pick which one you like. Then you see what store