What I truly love about this scubaboard is that there is so much talent on it, and great feedback on every issue under the sun.
OK, I stand corrected on IANTD Advanced Nitrox: you only get certified to EAN50 apparently, rather than all the way to 100% O2.
Now, my additional comments.
CCR ... what a way to die! I personally stay away from CCRs.
GUE ... hmmm ... now this deserves some further comment and thought as well.
Diving with the GUE crowd is like going to a nudist beach but with a swimsuit on. If you don't dive their way, then its the highway. No flexibility.
Also, if you are not a young robust diver, its the highway. They don't teach older or flabbier folks.
Also, GUE gear is called "halcyon." You will have to re-gear in halcyon stuff. That is not necessarily bad, as long as you have not already bought everything. Their gear is fine, and for some applications their gear is superb. Point being, you will have to throw away most of your 'old' gear.
Now, onto the subject of GUE egos. I have no problem with GUE graduates diving their own way. I have no problem with GUE grads thinking they are the best trained divers. However it does piss me off immensely to hear then SAY IT.
All I can say to that is: hey, buddy, lets step outside and settle this once and for all just between you and me!
(Whenever I have said this in the past, all of them have run away.)
I myself have tremendous respect for the tech programs of NAUI, IANTD, TDI, GUE, etc. Which is better depends completely on the individual diver that they graduate, on a case by case basis.