What are some alternatives?
When comparing RetroX and BizHawk, you can also consider the following products
RetroArch - RetroArch is a frontend for emulators, game engines and media players.
Happy Chick - Happy Chick emulates more than 18 systems all in one APP
MESS - Emulates most gaming systems that exist, emphasizing accuracy over speed.
higan - higan was formerly known as bsnes. The project was renamed after becoming a multi-system emulator.
OpenEmu - Console and Arcade video game emulator for macOS.
Mame - MAME stands for Multiple Arcade Machine Emulator.