What are the convenient cloud services for storing files?

Question

Backup

Hello.
I just can not find a cloud service that would suit me. The fact is that until recently I used bitcasa.com until I received a notification about its closure:

Bitcasa Drive Discontinued
This message is to inform you that the Bitcasa Drive service will no longer be supported. You will need to take action to avoid losing your files.
All data must be downloaded by 11:59pm PST on May 20, 2016, after which time all accounts and stored data on Bitcasa Drive will be permanently deleted.

Why did he suit me? In it, it was possible to select arbitrary folders on the disk for mirroring, and they did not need to be copied to a special folder, as implemented in Yandex.Disk, Cloud.Mail.ru, Dropbox, etc. If I cancel mirroring, then the files in the cloud remain, but, of course, they are not deleted on the local disk either.
Thus, I did not have to worry at all that some files might not be mirrored. From time to time I just ran the bitcasa application, and it synchronized all the data in the cloud with the local disk (folders selected for mirroring).
If I needed a backup for a certain number, then I simply copied the mirrored data in the cloud to another folder that was not mirrored with the local disk.
Is there a service now that would also allow you to synchronize files with the cloud?