I'm with Nick on the RR Adventure Top- a great piece for warm and hot weather. I also have the RR Weatherpants which use the same "2ply 3oz Quick Drying Duralite Nylon" as the Eco Mesh Pants (only without the insect shield and the reinforced sections). The Weatherpants have "reinforced seat and knees of railtex nylon" which seem to provide an extra level of durability during rocky scrambling- overall these pants do what they are designed to do very well in my experience. I wish they had some stretch to them, and that they handled snow better, but then they would be different pants!
I also agree with Nick that the mesh on the Eco Mesh Pants could be vulnerable to brush, but suppose that with some care one could zip and unzip the vents depending on trail conditions. In very hot weather, I have been hiking with convertible pants with the bottom attached but almost entirely unzipped- not a perfect solution, doesn't handle bugs, but when it is hot it sure is a relief. Makes the Eco Mesh Pants look interesting.