I have all three of these books.
The Machado book is excellent. Some really good techniques in there. But I am a BJJ novice and many of the techniques are too difficult for me to execute.
Royler's Submission book is the best of the series so far. There is some really important information on basic grips, drills, positions, etc. There are plenty of basic techniques. There are also some really difficult techniques. This is a great book for people of all skill levels.
The Passing the Guard Book discussed on e-Budo has been very helpful to me. It is very very detailed with lots of tips and pictures on what to do and what not to do. There is a chapter on passing the guard without standing up. I really need this right now because I popped my knee a few months ago and am unsteady doing a standing guard pass on anyone over about 175 lbs. I have actually used some of these techniques and they work. Proof is in the passing, so to speak.
As far as the controversy over the qualifications of the Passing the Guard authors--what a bunch of old-school nonsense. The critics fail to recognize two things: 1) It takes about 10 years to get a Black Belt in BJJ. Purple Belt is anywhere from 4 to 7 years. So, every BJJ Purple Belt has at least as much training experience as most TKD 1st or 2nd Degree Black Belts and many have as much experience as Kenpo 1st Degree Black Belts. 2) BJJ is only about 15 years old in the US and was virtually unknown until 10 years ago. As a result, there are relatively few American Black Belts and articulate English-literate BJJ Purple and Brown Belt how-to-book authors are providing a valuable service to the English-speaking BJJ community.