It's very simple. A Raid should just work in the background. Forget about it - till it doesn't work. I quote Walter Biscardi. So there are the costs. A good reliable raid system is expensive. We all know about it. So our professional recommondations for a system we care about are the usual choices. The main problems accur, when you don't have enough money, which most of us don't want to spent.
So for me as a senior video editor I want to get the best system available to be as creative as possible, and have the least thinking of "is my raid working properly". If you take this in mind the best raid is the cheapest raid. It just works at least five years without thinking about it.
So, what are your opinions about raids? What are your phillosophies.