Which QNAP 4-Bay deserves your Plex, 4K and NAS data? Which NAS should you Buy? Second only to the QNAP TS-453A, the QNAP TS-451+ is one of the best 4-bay NAS units from QNAP in the market this 2016. The design is the result of years of chassis design in previous unit and is very easy on the eye. A