Big fan of the stuff. Dave Gentry originally looked into it, if I remember right, but dropped interest in using it solely as a coating when Locktite said it's not UV resistant at all. It'd be nice if it was, but I end up painting over it with Rustoleum anyway. The PL isn't the prettiest stuff around.
It's tough. Knife will still cut through it, but it holds up to rocks and branches well. I wouldn't go rock gardening with one, sliding up on barnacle covered rocks and what not, but I've scraped it along shale edges when the Mohawk River is running low. It'll scrape the paint off, but that's easy to touch up.
Applies pretty easily; just spatula the stuff onto the fabric and work it into the weave. I've had some spots bubble in the past, likely due to me laying it a little too thick or excess moisture (I do most of my work outside on the yard or the porch). Let it cure for a couple days, wash it down, and then paint.