I have spent a significant amount of time on each and would suggest it's the only actual cloud. The others are data centers masquerading as a cloud, notice when us-east has issues for AWS, Azure had a spof dependency on a datacenter that didn't even have AZs... GCP is architecturally on another level. The others seem to be unaware of what 'cloud native' means, so if you are attempting cloud native on non clouds, you inherit their lack of foresight.