I topped MBW a few hours after applying with Optimum Car Wax. The combo is still holding the look after two hose washes and one waterless wash. If you want to stay with only OTC products, there is Meguiars Ultimate Qwik Wax. Both products are easy to use so I end up applying one or the other each month.
What I like about Meguiars Black Wax besides the way it darkens my paint and hides fine scratches is that it is also a cleaner wax. My old routine involved breaking out the polishers every six months to clean the paint and get the fine scratches. I'm an old guy so this was an all day job. With MBW, I get close to the same look in four hours and during the time I'm waiting to apply the topper, I can give my wheels some love and tackle the interior. Basically I use this product as a one step cleaner and glaze and it does an excellent job. I don't have a show car, just a well maintained daily driver.