Am considering Synology RS1619 vs. cheaper alternatives such as QNAP. Integrated backup is critical; I use iDrive now to back up a home-brew FreeNAS device which is at capacity and becoming unreliable.
As long as you don't get any value series NAS, you will get a full range of Synology backup functions. Any plus or XS series is good to go.
Qnap have basic backup such as RSYNC. Synology also support Windows server image backups etc.
I hope this helps.