I am happy with the Autosense OS on Phonak, and I think a lot of people with Phonaks are on this forum. There are some that have not been happy with it though, saying it changes programs haphazardly and is sometimes too slow/fast to react to events. Sometimes that will lead to them ending a trial with Phonak, and trialling another aid, other times it might be a case of more fine tuning required.
The Autosense OS can’t be switched off, as it’s the default program. When I don’t want to use it, I select Calm Situation, which is the 1st program in my setting. However - for noise etc, I usually use the Autosense OS. It’s pretty good I think - but that’s my personal experience. Sometimes I do have to manually select, but that’s only very occasional.