I have the cover for my ProAngler 16 and am very pleased with it. As for material, I don't know, cavas maybe, I never paid attention. The cover straps down around the trailer, and I have not had a problem with it. It stays tight while trailering, and keeps everything nice and dry and clean. It is reinforced around the trolling motor, windshield and tiedowns. My only complaint is the light color gets dirty easily and I haven't figured out the best way to clean it.
I ordered a custom cover from Bass Pro last year for my Pro 17 because the original cover was 6 years old and starting to leak and had a few small holes.
The custom cover is OK. I don't like the way the tie downs work on this cover. On the original cover, you had a set of tie downs for each side of the cover. This custom cover only has tie downs on one side that go all the way under the boat/trailer and connect on the other side. I like the older way better.
As for fabric, this new one seems to leak some water through in a couple of spots, at least on mine.
But you get what you pay for. I priced custom covers through a custom upholstery shop that does boat covers and their prices ranged from 400 to 1000 dollars. So I'll take my 150 dollar cover with it's flaws and just deal with it.
I got the towing cover with my Tracker. It's looks like it's a Grey vinyl coated canvas made by a company that starts with a 'D', don't have the literature with me right now. I really like it. It seems like a really heavy duty cover and is reinforced throughout. The only thing wrong with it is the TRACKER lettering is peeling off. It trailers really well although I don't like to trailer with the cover on unless I have to. Other than the lettering coming off I'm really satisfied with it.