My personal preference has been to us an AK120 or AK100 based on its physical size being very close to the Mojo connected with a custom optical cable. The AK120 holds two 256gb micro sd cards, but the library has a limit of 10k tracks. It makes for a nice portable setup event though it is a little over an inch thick. I have also tried the Shanling M1 connected through USB. The M1 takes one 256gb micro sd card. I am not a fan of using the usb connection on the Mojo because of it issues and UI for M1 is not very friendly, although it is functional. The M1 is smaller than the Mojo making it a little tricky to mount the M1 with the scroll wheel accessible. Also, the M1 uses a USB C connector so finding an OTG short cable is not easy. I'm not crazy about scroll wheels for navigating large music libraries so the M1 will not replace the AK120 for me. Hope you find my opinions helpful.