I've been a long time user of V-Slot extrusions, but was curious what the usage case/benefits of the open rail is. Why would you use open rail when there are fewer plates/mounting solutions, and less wheels that will work on it? Does it provide a higher level of repeatability/precision? Is it just stiffer due to the added material, a spacing thing, or legacy thing? I'm all about options, but curious where you would use this except where you needed to use the metal wheels since they can be hard on the V-slot. Looking forward to the comments.