Comparing Custom Firmwares

Features Stock Atmosphere Kosmos ReinX SXOS Notes
Free x (~$30 USD)
Open Source x
Firmware 9.1.0+ Support x ReiNX is DEAD Project now. ReiNX have not been updated since 8.1.0 :(
Homebrew Support ? Be aware: Many homebrew app authors do not support sxos.
Supports Custom Sysmodules not all sysmodules will work on sxos.
Realtime Cheat Engine sxos have laggy cheat engine. it lags game with cheats enabled.
Support Game Modding
Custom Themes need to add a fix for lock screen themes on sxos
Custom boot screens x you cannot change boot screen on sxos at all.
FS Patches
ES Patches Atmosphere & Kosmos Sigpatches must be installed manually
Configuration Tools x
Reboot to Payload
Proper Shutdown w/ AutoRCM x x
Button Remapping ? x Using hid-mitm.
Third-party controller support x sys-con or hid-mitm
XCI Loading/Mounting x x x XCIs can be converted to NSP for other CFWs
external hard drive support x x x external drive support is being worked on for atmosphere right now.
Fast on updating code when new switch fw is out x ReiNX have not been updated since 8.1.0 :(
Relevant Guide Here

✓ - Supported

? - Partial or incomplete support

✖ - No Support