trevinkorea:
Are the ANDI books better in terms of content. I really don't care what colour it is or how many pretty pictures it contains. I am after content.
I took the ANDI CSU course so I have the manual. I've also read the PADI EANx manual. I'll provide comments on both.
Just to preface my comments, as NWGratefulDiver correctly pointed out, comparing ANDI CSU and PADI EANx isn't "apples to apples". That said, both are recreational diving courses, albeit with distinctly different philosophy and objectives.
At the risk of making a sweeping generality, PADI provides very polished, high quality, well-edited material that has lots of nice pictures (including dive bunnies), but is short on content. The PADI EANx manual teaches you what you need to know to dive EANx 32/36 but little more. If all you want to do is dive nitrox to extend your NDL, this is the course for you. (No sarcasm intended!) In my humble opinion, the two certification dives for this course are a waste of time.
Like the course, the ANDI CSU manual is almost the alter-ego of PADI EANx manual. It's photocopied, it has typos and spelling mistakes, it has no pretty pictures, and it has a lot of dated (although not necessarily incorrect) examples, but it also has lots of detailed explanation about narcosis, oxygen toxicity (cns & whole-body), EAD, MOD, Best Mix, a variety of nitrox applications including accelerated decompression, and lots of information on oxygen safety and gas mixing. This course tries to tell you not only what to do, but also why to do it. The manual is completely self-contained. If you read it cover to cover, did the examples and took the quizzes, you would have very well-rounded knowledge of the material.
ASIDE: I'm glad to see padiscubapro's comment that the ANDI manuals are being re-written. When the already excellent content is tidied up and revised, it will be even better.
Whereas the PADI course is very focussed on a specific objective, the ANDI CSU course is intended as less of an end unto itself, but rather to be a foundation for other courses. If you have plans to some day do decompression diving, this course makes a good prerequisite. Additionally, depending on the instructor, you will get to experience two-mix nitrox diving with a sling bottle including OOA drills, gas switching and tons of other good stuff. (None of the practical diving skills are discussed in the manual.)
All of the above said, the two courses are both well-suited for their intended purposes, so DO NOT TAKE MY COMMENTS ON THE PADI EANX COURSE AS A SLAG.