I'm a retro computer lover at heart. I have more 8bit/16bit computers and consoles than you can shake a stick at. I restore, recap and retr0bright them and store them. When I want to play Lemmings on an Amiga or California Games on a C64, I reach for one of my dedicated emulator systems like AmiBerry.
I know the purists out there are saying: "Why own all those great systems and not use them?" I do use them from time to time, but seeing the number of systems that still work dwindle away daily, I prefer to keep my original systems locked away; safe and dry. With modern day emulators, the experience is almost dead on to the original.
Case in point: BMC64, a bare metal Commodore 64 emulator for the Raspberry Pi 2/3 with true 50hz/60hz smooth scrolling and low latency between the input and the video/audio.
There is no O/S to boot which means the emulator has direct access to the Pi's hardware resulting in better performance and a boot time of around 6 seconds!
You can even wire up a real DB9 Commodore joystick to the Pi's GPIO pins and use your competition pro joystick.
It also offers excellent audio/video synchronization and no need to issue a shutdown sequence to turn it off, just power it off when you are done.
There are a few issues though. No hot plug support for USB devices. All devices must be plugged in before the device is booted and removing them while the system is on will halt the emulator or make it slow down considerably. Also, some USB gamepads will require manual tweaking of the settings in order for them to work. All issues I'm sure will be addressed over time.