GCP got really, really good in the last few years. The cross-account story is now better on GCP than on AWS. BigQuery, Spanner, Pub/Sub, GKE are all best-in-class. AWS has its advantages too: CloudFront, Lambda, S3, DynamoDB, and IPv6 support are all best-in-class. It really just depends on what your product's actual architectural needs are, and whether you have access to nosebleed budget to pay for it all (these services are all staggeringly expensive).

Cloud revenue is really concentrated now, AWS is the only mass market platform.

Everything else is “call for pricing” for all but the simplest use cases.