With an excellent user interface, a vast amount of features, and stellar performance, the Synology DS412+ is the best choice for now if you want a four-bay network storage device for your home or small office.
Synology DiskStation DS412+ review: Synology DiskStation DS412+ - CNET
Synology DS412+ DiskStation Reviewed - SmallNetBuilder
Synology DS412+ NAS Review
Synology DiskStation DS412+ 4-Bay All-In-1 NAS Server DS412+ B&H
Synology NAS Diskstation DS412+, Computers & Tech, Parts & Accessories, Networking on Carousell
Synology DS412+ NAS Review
Synology DS412+ NAS Review
Synology DiskStation DS412+ review: Synology DiskStation DS412+ - CNET
Synology DS412+ DiskStation Reviewed - SmallNetBuilder