The backup utility included with recent versions of Windows has issues backing up to network attached storage - I do not recall the exact problem, but I vaguely recall it being related to the utility being a limited edition (ie. deliberately crippled) version of Symantec/Seagate/Veritas BackupExec. Anyway - I have run into the problems and took the easy way out, the DNS-323's built-in scheduled downloader (which by the way can use CIFS/SMB).
The scheduled downloader may not meet everyone's requirements, but it meets mine - I have it scheduled to run nightly and copy specific data folders from my hard drives - I have chosen to backup my data, rather than my hard drive for reasons I will mention later.
I have not used Drive Clone Pro, but based on the name, I assume it would be some sort of "whole drive image" deal - if this is the sort of backup you want - Acronis True Image is similar in concept and works well with the DNS-323 - although you do need to verify that the boot image it creates will work with the network card in your computer - and I will use this last statement to lead into why I do not backup my entire hard drive.
Whether or not the "whole drive image" style of backup works for you MAY be dependent on the hardware you are a) backing up from and b) restoring to - this has a bigger impact than the type of network target device does.
I have used True Image on a number of occasions to create a whole drive backup whilst "upgrading" to a larger hard drive, and it has generally worked well, however, depending on the specific hardware involved it may fail if the boot image it creates does not include drivers for your network card, or, in my case, RAID controllers - and this is one of the reasons why I do not use this style of backup.
Several "whole disk image" backup utility vendors (including Acronis & Symantec/Seagate/Veritas) claim to offer what is known as "bare metal" restores - or the ability to restore the disk image without having to first re-install the operating system and backup software - I have tested several and none so far have been able to load my RAID controller drivers and automatically create the RAID volumes required.
A second reason to avoid "whole disk image" backups is that they may fail if the system being restored to does not have identical (and in some cases the exact SAME hardware) on which the backup was made - this is partly a driver issue - if there have been signficant hardware changes the restored OS image may not have the required drives and may fail to boot (worst case scenario), or will boot and require extensive work to be done to get the system into a usable condition.
Of even greater concern however, at least for Windows users, is Microsoft's "Windows Genuine Advantage" anti-piracy methods, which create a "hardware ID" which is then stored on the drive and matched on every boot up - if you change the hardware sufficiently that the new ID generated does not match the stored ID, Windows will flag itself as a pirate copy and lock you out.
This may happen with something seemingly as simple as the replacement of the system board with the identical part - I have had this happen with a Dell laptop - Dell says call Microsoft (it is a Microsoft issue and Dell lack the ability to generate a new Windows unlock), Microsoft says call Dell (Dell as a Microsoft OEM is responsible for providing support on the OS it supplies with the hardware), and you'll probably be told to buy a new OS license.
Believe me - it is a lot easier ( plus you end up with a cleaner and better running system) if you do a clean OS re-install, followed by the applications, updates, and then restore the data - it is however a lot more time consuming.