I do not care if the cat is black or white, what matters is it catches mice. Mango has four things going for it that ICS does not; serious battery life, consistently responsive UI, a predicable mobile browser, and a terrifically organized API. None of those properties have a strong dependency on the underling kernel design.
When I had my Windows7 phone, it never crashed. My Android phone, on the other hand, crashed all the time. Although I enjoy using my iPhone, the kernel really sucks at memory management. If there is anything that a kernel should be responsible for, it would be that-- And when I say sucks, I'm talking from my perspective as a developer, not as a consumer.