equiniphile- Yep, what riccil0ve said is very true. You have to be a bit careful with it but when it works, it WORKS. And the sun burn/sun bleaching seems to be combatted pretty well by what I've been doing with my guy's black hair..I'm sure to either apply the MTG when it's dark or cloudy or when he's going to be under covers for awhile, and I always follow it by a pretty heavy application of Absorbine's Santa Fe detangler spray (which is great for the hair AND has sunscreen in it), then I braid the hair and bag his tail. So far his hair is staying pretty black.
It definitely is very greasy though. But I think it's a pretty small price to pay for the incredible results! And all you have to do is just give it a good wash and it's back to normal.
You only have to use it once a week max so it's not too bad. Plenty of people use it every other week or even once every month or every other month and still get some pretty great results.
And I should also note, giving it a really light trim first really does wonders, too.
So if you're willing to put out the effort, it definitely could help you with your guy. =)