I’ve used both and prefer DH’s panel over CPanel–though the DH panel can be slow at times.
When you use your host’s file manager, are you backing everything up to your own computer? If so, good–but I haven’t met many people that do. They generally make changes then leave the backups to the host.
If you edit them locally on your machine, then upload with an FTP program, you know that what’s on your computer is always a current backup of what’s on the web (not including things that change, like databases, etc… if applicable).
DH backs the servers up, but if anything you have is important, you should always back it up yourself, too.
I use Bulletproof FTP (bpftp.com), but it isn’t free. Filezilla seems to be a popular choice and you can download it for free at http://sourceforge.net/projects/filezilla/