AOCS was for pilots, NFOs and AIO (aviation intelligence officers). Everyone else went to OCS at Newport, RI and they started classes of 200 with 190 or so commissioning. COS had maybe a 5% attrition rate. ACOS had a 65-75% attrition rate (my class started with 78 and commissioned 21. My brother's started with about 80 and commissioned about 20). It was a different time and a different culture.
After I got commissioned, I ran into a couple of the DIs in a Pensacola bar and bought them a few beers. They told me that most of the AOCS DIs had already completed tours as Marine OCS DIs and perferred AOCS because it had far fewer rules they had to follow than Marine OCS. AOCS let them use their imaginations in the most wicked and devious way possible. They continued to say that they respected every single officer that commissioned out of AOCS because they survived the hell the DIs put them through. They said that wasn't necessarily true of those commissioned from Marine OCS because the rules weakened the DI effectiveness. Again, this was the early 80s, not today. I have know idea what the DIs would think today but I suspect it is much harder to make it through Marine OCS now than Navy OCS.