In terms of hardware, RDX cartridges are just bog-standard SATA hard drives in proprietary enclosures, so no more or less reliable than SATA hard drives in equi

In terms of hardware, RDX cartridges are just bog-standard SATA hard drives in proprietary enclosures, so no more or less reliable than SATA hard drives in equivalently rugged USB enclosures. I'd actually argue that RDX carts are a bit worse than ordinary USB external hard drives in long-term archival applications, due to an unusual design decision: the SATA hard drives internal to RDX cartridges are locked with factory-preset ATA passwords that serve no apparent purpose other than to make them non-interoperable with standard SATA ports and enclosures, which are more common than RDX drives by several orders of magnitude.