You don't need to use gcloud to ssh. Just add your keys in your projects' Metadata, and you'll have ssh access to all servers.
Each member of your team can do it, and it works retroactively.
Each member of your team can do it, and it works retroactively.
In conclusion, I guess both ways aren't bad. I just seem to prefer AWS here because for me it was a bit easier than GCP because I ran into several problems when sshing to GCP initially.