They don't have a great story around extensions - the ones they do have are unsupported/buggy. For example, PostGIS is missing "ST_FromGeoJSON" because it was compiled with the wrong flag - and has been this way for over a year despite hundreds of user complaints.
As someone who was migrating from on-premises to gcp, and who needs extensive postgis support, this information is a deal breaker for me. Is there any place I can find more information about postgis and other extensions status? Are you aware of any other bug related to postgis?
They're all the same quality. Sometimes great, sometimes terrible, but will get the job done as long as you put in the effort. Also bigger customers will obviously get more.