Black WOW! works well, a bit pricey and sometimes tedious to use. IME, it works best on pebble-grained and textured vinyl. On smooth glossy surfaces it can get smeary. Best results with BW are obtained using extremely small amounts.... which is what can get tedious spreading those tiny amounts over large surfaces.
Mother's Back to Black restores and preserves and I've had good results with longevity. It's relatively cheap which means you can slather it on faster and easier than BW then buff off the excess to get rid of any greasy look or excess. It's much easier to wipe off if you get it on paint.... BW is really tough to remove after you get it on a painted surface. B2B does leave a bit of a gloss until it's washed.
I recently used 303 Protectant on a tonneau cover and was impressed with it's cleaning abilities and natural look. I'd always just used it for interiors. I tried it on black bumper and window trim and so far it's lasted through several washes and everything a NE Ohio winter has thrown at it. Probably one of the easiest, trouble-free solutions, IMO.
The whole secret to large areas of black panels is to not let it dry out, oxidize and start graying in the first place. Like most things, it's easier to take care of in the first place rather than try to restore it later.
That black on white is a nice combo. DO avoid getting waxes or polish on the edges of the black as it looks like crap and is sometimes very tough to remove.
TL
