The MiSTer is a truly wonderful piece of kit if you're into your retro games. Using Field Programmable Gate Array technology, MiSTer is capable of replicating the performance of a whole host of consoles, computers and handhelds with amazing accuracy, thanks to the fact that it uses hardware rather than software emulation; in short, the MiSTer can configure itself to behave exactly like a classic gaming system.
However, unlike other emulation options, such as the surprisingly user-friendly Polymega and the rather more straightforward FPGA handheld Analogue Pocket, MiSTer isn't strictly a commercial product but one that is driven by the community around it. Therefore, it requires a little more effort to get up and running, and is constantly evolving and changing.