This is a LIFE saver, I have Retroarch setup for all of my systems, the only console systems I do not use it for are:
32X - Kega Fusion, don't care for picodrive
PS1 - Mednafen, yes there is a retroarch core but it doesn't support guncon/justifier/mouse currently, once support is added (if it is, then I will switch)
It gets a lot of flak (Retroarch) but if you save each emulator settings to their own config, it works great!