IMHO, round tubes cause leaks in the crotch of waders, I have used Orvis and White River, neoprene and lightweight, not much difference in the live expection of one over the other. I am currently fishing out of a Fishcat (about 3 years) techincally a U shapped tube and have no evidence of wear in the crotch in White River I am currently wearing. When I crawl out after my little inverted adventure I could find no evidence of wear or tears on the knees or other areas. I am very happy with them for the prices.
I did recently fish with a guy who said the White River did not hold up well to "briar busting" necessary to access some streams as well as the Simms he was wearing but he had a deal where he was getting them as wholesale.