It ran Monkey Hero for a long time before Beetle was updated to support that game. I don’t know if either is 100% compatible with the library, but both are pretty up there. Personally, I really like how Swan’s core options are laid out. Beetle’s were more messy last time I looked at them.
You can enable Dualshock globally in Swan and it doesn’t mess up certain games that didn’t support analog, like SOTN. You do have to manually enable analog for some games that support it, but don’t enable it themselves, like Crash 2 though. You can force it on with a game specific core option for those, or just press the analog enable combo every time you launch that game.
Also, SwanStation is great for native res emulation, since it also has a software renderer. It’s based on Mednafen’s just like Beetle’s. When using software renderers, I haven’t found an instance yet where there was a noticeable difference visually or audibly between the two. So I disagree that it’s only good for graphical enhancements.
Since Swan has better options and is faster than Beetle (great for fast forwarding 10x through loading screens), it just seems better all around to me. Though I would be interested to see any comparisons that showed accuracy or compatibility differences.