I love them!
This set of roof bars is really convenient for carrying something long such as pipes and ladders. You don't need to rent trucks from DIY stores with this set of bars. However, one of the shortcomings are the covers which are supposed to attached to the end of the bars; you might lose them before you know it. I taped up the covers and bars with a black insulating tape and opened 4 holes by my drill drivers for waterproof, just in case. What if you neglect to do so? - Eventually, water may get into the bars and corrode them.
Anyway, you will need the bar set if you want to carry surfboards, ski and snowboards and long bars!