It rarely if ever works properly with standard Linux or Windows tools (s3), it has a rat's nest of arbitrary restrictions which require a language lawyer to decypher (s3/iam/vpc/roles), the APIs are vendor specific and sometimes even region specific (s3), the APIs are obtuse (s3 multipart), the clients are buggy (boto/boto3), suddenly you inherit extra costs and configuration requirements if you want to do something like expose it over http (route53/cloudfront/s3), credential storage is a nightmare for distribution compared to rsync/ssh etc. Ugh.
Please note I have used Google Storage as well and all of the above also apply.
The only thing that is positive is capital expenditure is low.