Actually neither one contains any wax at all, both are synthetic sealants. I have and use the Qwik Wax, it works well and is quick & easy to apply. I believe the paste version has more longevity than the spray.
Because the word "WAX" sells. Sealant means nothing to the average Joe. With a few exceptions a true wax is gone within 4-6 weeks. A sealant can last 6 months or longer with proper surface preparation. Megs touts the paste as their longest lasting. Use it and touch up with the spray as needed....on a clean car of course.