RetroArch is the go-to for most people, because it can emulate just about anything. But first time setup can be kind of a pain if you’ve never done it before; The UI for settings can be unintuitive, you need to dig for what you want, and it’s easy to forget to save your settings because the save option is in an entirely separate page. It also suffers from some software bloat, because it has so many features that it can get bogged down when emulating more intensive systems.
For Nintendo I tend to use Delta. It’s simple, has cloud saves via Google Drive, and runs everything flawlessly. For PSX, I tend to use Gamma. Again, it has a simple interface and syncs via Google Drive.
The biggest counterpoint I have is simply that I enjoy camping. Good luck finding a desk lamp when you’re 5 miles into the woods. And I’m not wasting my flashlight’s precious battery life on reading.