I spoke to steve at calmini recently and he gave me some info on a lot of his products. The pictured skid plate is not the final production piece. The final piece which is now being built does have an angled front similar to the skid row design so that sliding over rocks will be a lot easier. That is gonna be the only major difference between the pictured and final version.
I have the skid row gas tank plate and I can tell you that it does catch a lot of sand, dirt and mud. I don't mind too much stiking a hose in there and flushing most of that stuff out but if you don't do this regularly I am sure it can become a problem.