When using Forge 13.20.0.2205 with Minecraft 1.11.2, Better FPS causes a launch failure. At least, the failure stops occurring when Better FPS is removed from the 'mods' folder and recurs when added back to the 'mods' folder. However, I don't see anything in the Log or error messages to pin the problem on Better FPS - I had to individually add/remove mods to track down the cause.

fml-client-latest.log.txt

Currently, the last version only works in 1.11. A new version for 1.11.2 is coming soon :)