If they are anything like the Naugasoft that Sailrite
sells, they'll hold up extremely well. In hot weather
you'll probably want a towel or something to keep from sticking to the cushion. In cold weather
you won't notice much, particularly since you won't be wearing shorts or swim suits.
When I did ours my lady wanted white, I tried to discourage her but white it was. There was no problem with mold
or mildew that a simple wipe down didn't prevent but they did show the dirt and a couple got stained. Now I'm re-doing in a fabric
Dimensionally, they are much more stable than fabric
and were easier to sew because of the lack of stretch. I don't know about the products you've listed but the naugasoft appears to be darn near indestructible. I tried to poke a screwdriver through a scrap and it wouldn't go.
Probably any of them would work just fine. If not, you get to do the job again....like me.