My company also used all 3 (at a very large scale / spends). MS was nice, but useless / incompetent technically. Anything non-trivial took forever to get a straight answer or resolve. We rarely got to speak directly to anyone with real expertise.

AWS, we could speak directly to Sr engineers on the relevant team. Full transparency, highly responsive. They were clearly trying to understand our issues and suggest change for both us and themselves.

Google was mostly useless. There was one team I got to talk directly to, who were great. But that was the exception.