From reddit
"Android dev on the Kodi team left and had his own fork out called SPMC."
"It's not supposed to feel much different. It's just Kodi with some Android-specific code that was not part of the main Kodi project. For example, a while back, SPMC supported hardware acceleration on more devices than vanilla Kodi did."
"HD sound support is probably the biggest change for most people. If you're using with an Android TV device it will allow for integration with the home screen and voice search."
"SPMC has over Kodi:
HD Audio passthrough
Add possibility to choose IEC or RAW passthrough (via passthrough device)
Autostart at boot (this is huge for wife friendly factor)
GUI size setting (Allow 4k gui on Shield)
Only give codec priority to Mediacodec(Surface) for 4K
Android TV recommendations and voice search
SSL enabled MySql
Setting to force SMB v1
Basic Bluray 3D iso playback
Stop video playback when screen goes off
The ever good ol' "Import All" option
Add reboot & shutdown on rooted devices
Add support for AudioFormat::ENCODING_IEC61937 (Android N IEC passthrough)
Boost center channel on downmix
HQ scalers
GUI selection of H/W decoders
additional "ffmpeg" s/w deinterlace (this is a huge one for many)"
for normal user like me.. it good enough already