I don't think there is a preference for SEO and if there is, the benefit is marginal. I would personally choose to go with the .com or TLD version as users will most likely recognize brand websites and could lead to higher CTR. You do stand to run into a problem if brands have sub-brands or similar brands compete with a brand.
For example, people would search for "apple coupons" just as they would "iphone coupons" however iphones fall under apple.com site and not on their own site like iphone.com. Coupon sites have taken this into consideration and have the sub-brand (iphone) under the brand (apple) category like this:
Home > Electronics > Apple > iPhone
Think about how you would handle these scenarios on the backend in your database to help decide what is best/easiest for your team.