I've had cheap ones, and expensive but lightweight ones blow out the seams and fail almost immediately. I've had (non-goretex) "waterproof" jackets that leaked immediately with pressure from pack shoulder straps, or brush. The bomb-proof 3 layer pro-shell jackets are going to be much more durable, at the expense of heavier and not as breathable.
Also - gore-tex has multiple laminate / fabric types.
The sitka vapor is $300 because sitka fanatics will pay it.What he said. There are so many variables to Gore-Tex materials, layers and types.
You pay more for durability at the end of the day. Although, you also pay more for the newest tech. The Sitka Vapor is $300 bucks and its an extremely light weight 1 layer Gore-Tex but the latest technology.