Pandora 3d saga is a multi-game arcade console that can be added to old single game arcade cabinets to turn them into multi-game machines. The system has built in wifi and Ethernet for easy download of new games. It can also use a usb key to add games to the internal storage. This makes it very simple to use and is a great upgrade for older single game machines.
There are a number of different models of pandora box available and identifying which is best can be tricky. The earliest versions were the PB4 and PB5 which used an ARM A7 chip and supported 15hz CRT CGA screens. Since then a lot of third party clones have emerged using the PB4 spec and chipset with some not being as powerful as others.
The latest release is the EX2 pandoras box which uses a separate motherboard with the NAND on board. It is capable of 720p output via HDMI and plays nice with external gamepads. This is the first model to support a full 4K resolution and it can display a widescreen image on your TV (as long as you set the screen to the correct aspect ratio).
There are some downsides however. The CPU and GPU are not ideally suited to running demanding arcade games and you will often notice lag/ frame skipping. The other issue is that a lot of these games were not designed to be played on modern HDTVs and they can look stretched unless your TV has a built in 4:3 aspect ratio option.