First off, let me just say much respect to Mr. Luty. The fact that he went to prison over this book tells us more than we think. This is a good book and is probably better than most, if not all, "do it yourself" gun guides on the market (but I haven't read many). It doesn't require a whole machinist workshop, it doesn't require a lot of money, and the weapon could be produced in bulk if necessary. I haven't built it yet, so some of that could prove untrue. I don't think Mr. Luty has lied to us though. If you want details on durability, accuracy, etc., you're going to have to ask someone who has built it. I would assume that any problems with the gun Mr. Luty did not cover could be easily solved.
Now, this book is not really a laymen's guide to building a submachine gun, but as I said, it does not require a lot. If you have some good experience with tools, you will have no problems. Geez, if you had Shop in high school, you probably won't struggle much. Me? Nah, the ATF can breathe one more sigh of relief. I'd probably drill holes in my fingers before I got anywhere near the lower receiver! Don't get me wrong, anyone can do this but I suggest you have someone with a decent amount of workshop experience around if you're not familiar with the tools or materials. I opened the book, looked at the tools and on a few, I just went "huh?" Coming from a family of carpenters, I suspect they would be ashamed. Meh, maybe they would just be ashamed to know I had the book. It's a moot point though.
So if you have some experience with building things, specifically out of steel tubes, you can probably build this. If you know what a countersink tool is... ehhh... you're ahead of me. The bottom line is that if you think you can build the thing, you probably can (for display only and with the proper licenses, of course).
Oh, and thankfully there IS a picture of the finished product and it DOES look pretty cool, if you ask me.