We've had our Wally Sinker since '07. Public lake, lots of traffic on weekends. We've had anchors dragged thru the course, wakeboard/surf boats hit our fill buoy, etc, but all in all it's a really good system. Any water that gets into lines is easily purged. No problems other than routine maintenance. The most damage we ever had was self-induced. The air line separated from the SS mainline cable (supposed to be ziptied) and we caught it with the prop. Took about an hour to fix.
Our course sits fully on bottom (we don't dangle the sand bags). Depth runs from 12-17 ft.
We purchased full course from Wally so no experience with portable. Spoke with him many times on phone. Gives FULL product support.
We use 3-4 times/week spring-fall. Winter varies. Perfect for us on public lake. When we aren't skiing the course 'isn't' there.