BSNes is 100% compatible with everything. Every single SNes software works on it, perfectly, even the extra chips. It's the only emulator that's like that and you need a faster-than-usual computer to use it. It probably wouldn't run smoothly on a Nintendo Wii. Now, if you want to play Legend of Zelda: Link to the Past, you don't really need the most accurate emulator in the universe. As long as the emulator you're using plays that, it's good for you.
Different approaches for different problems.