I'm on my 3rd year with a set of the Simms Freestones and have been satisfied with them. Not jump up and down in rapture, but satisfied. I had to do the seams on both legs with A-seal this spring, but otherwise they've been good. The only others I've perhaps liked a bit better were the Beans Kennebecs which were just as durable and not quite so much like putting on a suit of armor. The Simms are fairly substantial, but I suppose that's part of the durability. And as with a lot of stuff sold by a variety of folks, as soon as Beans found out I liked the Kennebecs, they stopped making them.. So, they're out I guess.
I have a good buddy who usually buys the Dan Bailey wading pants and they last him twice as long as any pair of any brand has lasted me. But unlike me, he watches where he walks and is pretty fussy care-wise.
I know nothing about Patagonia other than it is almost Summer down there..