I just tried a 400 in 1 Game Box this sunday.
It is interresting. The PCB itself look nice and build professionnaly.
The Front End is ArcadeOS (i don't really like it, not really readable on the screen). The set of games provided with the board is very good and various. I just plays few of them , and it runs very well. Lot of text and loading screen are in Japanese (or chinese) language...
There is lot of switch on the board which allow to customize your configuration. The documentation is off course in Japanese or chinese , so not easy to find the right settings. There are different way to manage credit , to select if you want start on a game or on front end..etc..etc..
The PCB can be a good choice for who don't want put a PC / JPAC in their cab. The price could seems expensive , but when you see the board you can imagine there is lot of work of R&D behind , so you have to pay for it.
But for sure , the card is no more than an on board PC with MAME and Arcade OS. So except the Board itself, you can easly do the same thing for less than 400$.