I installed the Revolver X4 about a month ago, and so far, Im pretty happy. I like that it is very low profile and that it is rigid but can still be rolled up to open the bed without covering the rear window. The Revolver will leak a little around the tailgate, especially if you spray water directly at it, but my experience is that all covers will leak a little bit.
In my previous truck, I had an aluminum "A" series Roll 'n Lock which was pretty expensive at about $1,600. The Roll 'n Lock worked ok, but leaked worse than the Revolver and had hardware breaking after about a year and a half. I think all bed covers have compromises. Its just about picking the cover which has the compromises you can live with best.