When I pulled the trigger on a RetroTink 4K a couple years ago, I knew that I eventually wanted to get a MiSTer to complete my all-in-one setup. I considered building my own, but I was worried about making an expensive mistake while building it, so after a couple years of waiting, I decided to put in for the restock notice for the MiSTer Addons bundle to go back in stock.
This is among the most fun and unique gaming hardware I own. Playing games with hardware emulation and using RetroAchievements is pretty cool. Not necessarily the most intuitive setup process and interface, but both MiSTer Addons and the MiSTer project itself have guides for setting things up.
Everything is high quality, from the metal case to the USB-C cable which has a display for wattage. The rubber dust covers for the ports are unexpected but extremely appreciated. This is exactly what someone selling an open-source project should provide: high quality, thoughtful parts. It was nicely packed and shipped quickly.
The MiSTer project has pretty good scanline and aperture mask features, but pairing this with the RT4K is spectacular. Using Wobbling Pixels' profiles, particularly his new CRT Blend profiles for systems like SNES, Genesis, Saturn, and PS1, are the closest I've ever come to feeling like I'm actually emulating a CRT.
This is an expensive product, and you don't NEED it to emulate your favorite games. But man, if it isn't fun and engaging to do it this way.