What does each of them have different? DS420j vs. DS418 vs. DS423 vs. DS420+ vs. DS423+ vs. DS923+ vs DVA3221. DS423 Good for multimedia using Synology Apps (h264 support) (Plex and h265 seem to be an issue) DS423+ Good for multimedia and easy backup functions and is upgradeable. Has high availability option. Now two extra CPU […]