The Marantz SACD-10 still uses the long standing SACD-M3 transport, just like the SA-KI Ruby. and the SA-10 reference players that preceded it. These transports are difficult and expensive to manufacture. Manufacture of this device ended in July 2024. Google: Marantz SACD-M3 transport to read about it. Once they are gone, it’s over.
In the HIFI News review of the SACD-10, the SACD-M3 transport was specifically named. The reviewer hooked up the SACD-10 to a dcs system worth 20 times the cost of the Marantz unit and noticed an improvement in sound quality. You have many options with a machine like the SACD-10. And yes, the SACD-10 does sound better than its predecessors. How much is subjective.
Marantz does not stockpile or manufacture old parts like Accuphase. So if longevity is paramount. That might be a consideration.