I generally prefer RetroArch. It’s a bit of a bear to get used to and configure, but once you learn it or get it set up well, it “just works”. Plus, being able to navigate everything with just the controller is incredibly convenient.
On top of that, the settings, saves, and savestates are compatible in retroarch running on any platform. That’s not such a big deal anymore that a lot of emulators have releases on multiple platforms, but it’s nice to be able to start a game on say, my phone, and pick it up on my desktop.
And I can’t get over the sheer depth of what you can do with shaders with it. I store my games in folders by console, so I can set up one preset and apply it to all games in a folder.
All that said, in my experience it doesn’t do great with consoles after the PS1 era. Dolphin is slower than standalone and afaik is a much older revision, I never even tried the mess of the experimental PS2 core, and while these aren’t much of a problem anymore the PPSSPP and DeSmume cores used to be pretty rough compared to standalone.
If you’re emulating newer stuff, I’d suggest standalone emulators. If you only want to emulate a few things, skip the configuration mess and go standalone.
If you have a large library to emulate, the up front config work of RetroArch is absolutely worth it. If you have a few things to emulate from PS1/N64, it might be worth it to use RetroArch just to avoid the plugin hell of standalone emulators for those systems. If you like being able to plug in a controller and just go, not touching your keyboard or mouse again until you’re done gaming, it’s worth it. If you want to fiddle with things like black frame insertion, run ahead, and shaders to get the best quality video output possible, it’s worth it.