From your posts you seem to be passionate about your study of aikido. I wonder if there is any reason that would keep you from going and checking out some of this "IS" stuff in person?
With all respect,
If you had read all my posts (a hard thing to do at this point) you would know that I have said all along that it's ok to look at different arts. Doshu said so himself in the Preface to Aikido and the Chinese Martial Arts (Sugawara and Xing) in 1995.
It is difficult to know what the IS being discussed is. Hunter gives us an example of a Sensei he trains with. Harden says what I do is better. Harden says he can see that he can see from a video that it's not the real Aiki he's showing, and yet it is often said that we cannot see the secret he has, and that O Sensei had, unless we know the secret. Starts to sound like invisible clothing of the finest invisible silk. So I don't know what this Aiki is supposed to be. No one has bothered to define it. Some say it's Daito-ryu. Others say its Chinese. If "it" exists it can be described. The failure to do so raises my suspicions.
That does not mean that what they are doing, whatever it is, is not good on it's own terms. The fact that it may be good does not tell us how it translates to Aikido and does not support the wild claims that have been made. They are describing a skill set which is not Aikido. It may be PART of Aikido already. It is not Aikido. O Sensei continued to develop the art of Aikido up until the end. It was never perfected. Saotome Sensei told me this personally. That's good enough for me.
Having said that, I personally will not train with people who repeatedly make such bold statements that contradict what my teacher has told us about what O Sensei told him. For example, we again have Mark claiming that O Sensei didn't teach much. Completely false. Saotome Sensei has written that he took ukemi from O Sensei almost every day. Mark is implying that Saotome is not telling the truth. I will not, personally, train with people who do such things. I don't care how good they are. You asked me a personal question, so I answered it on a personal level.
I have been exposed to other complimentary arts and their application to Aikido far more than you realize. Though I am reminded often that I am a low rank non Budo man, I have been around many great martial artists. I am not opposed to people doing whatever they want outside of Aikido and bringing in the parts that don't get in the way of other people continuing to train AIKIDO. If they start insisting on their notion of Aiki (meaning whatever this IS Aiki is) then I have a problem with it. Smoke if you want. Just don't smoke next to me.