Yes, I moved from AWS to GCP while a product was in a late release cycle.
I talk about it in detail in a google cloud podcast: https://www.gcppodcast.com/post/episode-265-sharkmob-games-w...
The primary reasons were: Ease of Use, Support and Cost (in that order).
I had a bunch of what I call "3am topics" which inhibited our ability to perform stressful operations in the middle of the night meaning we minimise our opportunity of successful outcomes when on-call... I'm not a fan of that.
I also argued (quite successfully) the case that AWS was not saving us money or much time when the alternative was renting a handful of servers from a provider.
There were attempts by AWS staff to lock us into the platform but those services (cloudfront and ECS being large ones) worked so poorly that caching/reconciliation layers were added into the product to build resiliency: all that was needed was to replace what populated the cache with something else (eventually we moved to Kubernetes which worked much better).
Cloudformation was so hard to work with (at least our implementation) that replacing it with terraform was easy: the hard part was understanding what was needed and what was fluff.
We also had to care a _lot_ about how the network was setup in AWS, there were issues with MTUs not being aligned by default in some cases for example so we had to write workarounds, and the VPCs being zonal by default meant we had much more complex setups.
Another ease of use topic was the sizing of instances, instead of specifically saying what shape of machine most matches your workload in GCP you allocate a number of cores and you're kinda done. Another ease of use topic was that discounts are provided retroactively via sustained use (though, they do have commitments too) where as in AWS you needed to very carefully carve up your requirements to get significant discounts, or write your application to be as stateless as possible (which you can do in GCP too). This is not a lot better than physical machines because the upfront work of trying to capacity plan is still there... at least if you care about cost.
Regardless, our dev cycles are much more streamlined now, it's rather easy to deploy an entirely new environment, the operations can be handled by a single individual on a part-time basis, which in my opinion is the point of a cloud provider: to save you time.
I can go into much more detail if you have any specific questions.