Hi, I have been toying with the idea of Central storage for my macs...and new iMac that I am looking to buy. In classifieds there is a 5yr old Synology DS509+ with 5xWD 2TB HD. circa $500. Is this a good, average or bad deal? Would this be a good first move into a central storage solution, or should I be looking to get something far more modern..and perhaps a WD Mycloud etc... Thoughts?