I thought half the point of using copper or black pipe was to force heat transfer and make water condense out? Looks like a neat setup, and I could see how it would work, but seems to me that a relatively simple copper layout (if you can sweat pipe yourself) wouldn't be that much more.
I have heard that HF has trouble even getting the quick disconnects right, so I have an equally hard time believing this will hold air or hold up over time. Looks nice in pictures, though.
We all hear the HF bad mouth. Untill you have used an item I don't feel someone else's comment should be passed on. I have plenty of HF quick disconnects in my home "HOBBY" shop and also in our shop at work. None of this stuff is used hard all day. It has been working fine for me for years. I do have a friend who does use such tools all day, everyday, and he uses some HF stuff without complaint. If he knows a certain tool will be used a lot he may buy a better quality product. Although I have heard him , and others, comment that a particular HF item works just as well as one costing a good deal more.
As far as the Rapid Air stuff, I recently installed some at home. It seems fine to me. Now if you think that it is important for others to come in your shop and be in awe of your plumbing, don't use it. At least not if you have to do it on the wall. If you can hide it in the wall, it would be fine. It is very hard to get laid out straight. I laid mine out in the drive on a warm sunny day and it was no easier to get the roll to lay straight. That said, it did exactly what I wanted, air supplied to various areas of my shop quickly. I certainly wish I had known HF was going to do this since it has about half of what I paid. If I get a chance to stop by, and they have it at the retail stores, I will look at what they have. Looks the same to me with the exception of the tubing. Rapid Air tube is smooth, the picture of HF's looks ribbed. Joe