Hi Dennis,
The machines are great and work using Legacy and KP3 boards so bonus there.
The games use a combination of PROM chips and CF cards, games and be hard to come by for either platform but no more than others out there.
The issues you may have heard about are self inflicted by the manufacure and user for failing to perform required maintenance cleaning out dust and smoke buildup causes all machines to overheat. The issues go away when you take care of them as suggested.
The KP3 platforms which have dynamic buttons are the Podium Selexion, Concerto and KP3.5 boards found on the new Cresents which have different dynamic buttons over Podium. There are three different types of dynamic button panels on the latest cabinets so the latest are like the iDeck with no physical buttons where as the Concerto and Podium use LED buttons with different configurations and layouts resulting in different part numbers.
Switching games on KP3 requires you only replace the modules card which contains the game and following that you must do a RAM clear procedure in order for the game to load after swapping. Straigt forward process you've most likley already done with other machines.
All machines have heat issues but proper maintenanice and board handling prevents troubles not to mention power conditioning provided by a really good UPS.
Keep it clean and they stay cool and run great, they are just as good as the K2V but higher in price only because they incorporate Intel Atom processors on the graphics control COM express module and Intel Core i7 on the MPU/CPU COM Express module which DDR3 1333Mhz RAM vs the K2V using Konami internal components which is the main reason for super high costs; that and the ATI custom graphics card on board among other things.
When you buy one and need games PM me and I will see if I have anything you like.
Thanks Buddy,
Justin