Bumping this to the top...
Ordered a roll of the PostCoats, came in a few days later, we just haven't had an opportunity to test it until now.
Works more or less as advertised. If you're looking to make a high-end "nice" post for a high-dollar sign, this is not the solution. But if you need to ready a couple 4x4s quickly for a cheap real estate sign, I think it'll work fine.
It's not necessarily slow to put on, but it's a little tedious, I wouldn't want to have to do a stack of 20 or 30 posts, I think I'd lose my mind. Once we got going it took about 8-10 minutes to do an 8' 4x4. That's not too bad, I think we could paint them in significantly less time, but paint requires usually a couple coats to look decent, and takes a couple days to dry fully for handling, so overall, this would be a tremendous time saver if in 15-20 minutes you can have a set of posts coated and ready to install with no drying time.
The biggest downside I saw to it is it's not very opaque, or at least the white wasn't. On a raw pressure-treated post the white took on more of a dull off-white/grayish tint because the color of the underlying wood showed through a little. It's not terrible, and again, for quick and dirty realty signs it's perfectly passable, but it's not a brilliant white for sure.
We recycle a lot of 4x4s for one of our real estate customers, when we remove a sign from a property, we store the posts and reuse them. At any time we can have 20 or more old 4x4s sitting out back. They're all painted white, but usually after being installed and removed a couple times the paint can be pretty beat up so usually we need to repaint them here and there. This will be a great solution for that, the posts are already white so putting the PostCoat on it just freshens it up, no messy cleaning and repainting needed, just coat them before they leave the shop for reinstallation.
Anyway, for the money, it's a good product, we'll use it for sure.