Synology RackStation RS1221chat_bubble_outlineFrom real comments

Networking and caching options are the biggest sticking point for prospective buyers. Multiple commenters note the RS1221+ can't combine NVMe cache with dual or quad 10G NICs, unlike the cheaper DS1821+, and lacks any 10GbE/SFP+ on the motherboard by default. For a rack-mounted NAS over a thousand dollars, several feel 10-gig or better should be standard rather than an upsell, calling the omission shortsighted and 'nerfed' for 2021/2022 hardware.

The RP+ dual power supply placement frustrates users expecting true redundancy. Reviewers point out that swapping a failed PSU still requires downtime, defeating the purpose of a redundant supply, and call it a really bad design choice for an enterprise-oriented device that should be easily serviceable. One commenter also questions whether the ~$400 premium for the RP version is justified given it's essentially just a second PSU and different chassis.

Its compact, short rack depth is the standout practical advantage. Several commenters specifically chose the RS1221+ because it was the most compact unit that fit their rack depth, with the non-RP model allowing use in small racks favored by small companies and enthusiasts. This depth advantage is mentioned as a key differentiator when few other rack NAS cases are available in similarly shallow form factors.