Some air coolers, the TOP-end maybe, if airflow is good.
There aren't many air coolers that beat a H100i when it is used on the top as an intake. And yes, it stays quiet.
Reliabiltiy is very relative, if one out a 10.000 fails, it's still worse than 0 out of a million air coolers, but it is a very small chance.
Usually the temp difference between "quiet" and "full speed" is 4-5 degrees on AiO's, it's the same on air.. so I wouldn't say they are louder either.
Have you considered a new case at all?
Nope, I like my case
There is no point looking any further since I am now 100% sure that the Noctua fits in my case.
You can always take a look at the Alpenfohn K2 which is the same size but cheaper. There is no performance difference.