I don't quite get the hate that Retroarch receives due to the UI. Regular emulators are okay provided you have a mouse to click on everything, but when I want to just sit back on the sofa with my PS2 pad and flick back and forth between different systems using only the pad, and auto loading and saving of save states when I'm finished with a game, then Retroarch does it very comfortably. And often I use it with a $25 Android TV box, which runs the 8- and 16-bit systems perfectly.
I just turn it on, open Retroarch, look at the recently played games, pick one, and I'm in. When I'm finished, I go back to the menu and pick something else, all with my pad. I guess not everyone is happy with this, but it works for me. It's also my preferred method of playing PS1 on my PC.