Love it on my board when I have 2 pedals with same chassis and jack positioning. It has a few plus, such as how sturdy it is, and the fact that it will significantly help you reduce the "in-between pedals" space to a very minimum, especially if you wire up your pedalboard with a combination of these jacks and the Rockboard Flat patch ones. Great Stuff.
The only (maybe considerable) downside, is that whenever you wanna pull up or out altogether the pedal to which one of these is connected to, you might have to lift 2 or more pedals together from the Velcro. It can be a little tricky as the Velcro will pull back pretty hard, and maybe be slightly risky on the jack sockets of the pedal themselves. For that reason I have strategically chosen to use only a few on my board, and wherever they are, they are always isolated, so every 2 or 3 connections, to avoid having too many pedals connected with these and cause the problems I have mentioned above.
For the rest, as I said, top stuff!!!