For what it's worth, as a non-YC company, I found the GCP onboarding process to be far superior in every way, and my experiences were essentially reversed. For context, we started with GCP for Startups 1.5 years ago when we were just getting beyond a demo, and with AWS Activate 1 year ago, when we had almost no revenue and just about 1,000 users. We were based in the Santa Fe Business Incubator (NM, USA).

All in all, it had taken our incubator at least 1.5 years to get enrolled in AWS Activate, and 4 days in GCP for Startups.

When we applied for GCP for Startups, we were approved in a week, and were contacted right away by an account manager and a support engineer who offered us help with anything we needed. When we applied for Activate, it took a month with lots of followups, and being shuffled between 4 support team members who were communicating with the Activate team (there was no way to contact them directly).

It definitely felt like our business was important for GCP, and for AWS, it wasn't. It was an easy choice.