I am a huge advocate for full inclusion for many reasons. I have seen even severely disabled children (ie Cerebral Palsy, no functional communication, in a wheelchair, cognitive ability of a 1 year old) in a regular classroom. The student had a one-to-one aide. It was successful for all involved. The teacher learned as much as all the students did and it was very rewarding. However, there was buy-in from all parties. I have seen other instances where the teacher was not on board from the get-go and inclusion was a failure. The next year, that same child had a more open teacher and had a fantastic year. The teacher is the most important piece of a successful full-inclusion program.
In most cases, I am staunchly against self-contained classrooms. Unless the ratio is 2:1 or better, it is nearly impossible for the teachers to have the resources, time and energy to implement all those different IEP's. Also, these kids don't grow up and have self-contained grocery stores, a self-contained bank and a self-contained McDonalds. Everyone uses the same facility. If we teach our children early on to be accepting of each others differing abilities and that each of us has strengths and weaknesses, we will have stronger communities.
One of the more interesting programs I read about was in a school district here in California. They implemented a program called Neverstreaming. EVERY child was fully-included and then pulled out as needed for things like resource, speech, etc. The program was very successful. The federal law called IDEA is very clear: before a child is pulled out for any time at all or put in a different placement other than a general education classroom, ALL services and supports must be exhausted....this included one-to-one aides. This is rarely done. Usually what I see happening is that if a child struggles too much in general ed and/or is a low-scorer on standardized testing, the child is put in a self-contained classroom before all services and supports are tried in the general ed setting. When asked "off the record" why this is, administrators tell me it is all about money. School districts are insanely underfunded, but that is a whole other discussion......