I think it's fine if you treat the services as dumb remote hard drives, meaning you expect them to fail at any time and that anyone can simply browse it at will, so you keep other copies elsewhere and encrypt before uploading.
I have my important files backed up to S3 and to a VPS, besides a local HD, using git-annex, and it suffers from none of those problems. If my VPS provider goes bust or S3 eats my data, I just open a new account elsewhere and "git annex copy" the files to it.
I have my important files backed up to S3 and to a VPS, besides a local HD, using git-annex, and it suffers from none of those problems. If my VPS provider goes bust or S3 eats my data, I just open a new account elsewhere and "git annex copy" the files to it.