There's been a bit of discussion on the NXT Spray Wax over at Showcargarage.com not long ago. I may have seen some here as well.
Regarding compatibility with other products, I haven't used it but based on how its marketed I'd venture to say its not. Its meant as a booster to the NXT. You apply NXT Tech Wax, then you come back sometime later and apply some of the Spray Wax to rejuvenate the Tech Wax. If you had topped the NXT Tech Wax with S100 (for example) and then applied the Spray Wax over the S100, I don't know what you'd really accomplish. :nixweiss The S100 would act like a barrier between the Tech Wax and Spray Wax, don't you think?