Looks good. As others have said, the shopping cart on the side is a very good feature. However, as someone who often orders backups of particular models, I'd like it if there were also a "view/edit cart" button or something of that sort that allowed you to go to a dedicated cart page and change quantities. It looks like the "Checkout" button does take you to that sort of page, but adding a separate "view/edit cart" button would make it clearer where one should click to access such features.
Also, the little minus sign icon for removing single items from the cart is a bit small, and its function isn't clearly indicated without actually clicking on it to figure out what it does. So maybe you could make the icon bigger and/or label the column that it's in "remove item" (the same way the other columns are labeled "product", "qty", and "price") to make clearer what the button does.
