I have a Disco 1 with a 2in IronMan lift that has done the Cape and other trips. I also Have a D2a TD5 with a 2in IronMan lift that has done a bit of touring and a lot of country roads (dirt and corrugations) and can't fault it. I think most aftermarket systems die sooner or later, just like original systems do. Some just do it quicker than others.
I think if you are OK with the ride you get from your chosen system then you should be happy. But also remember, it will also degrade over time.