I have a similiar thing: The Popcorn Hour. Stocked with 2 TB. It plays mkv and BD ISOs and DVD ISOs and BD folder structures, DVD folder Structures and so on. Poorly the Firmware is not finished, yet, so its sometimes kinda buggy.
The big Popcorn Hour C-200 could contail a 2.5" SATA HD inside, and a 3.5 " SATA in an excange frame. Instead of the exchange frame there could be installed a BD-Rom for watching BDs. I belive its also possible to plug BD-Roms via USB. External HDs and Sticks could be plugged via USB and could be used to play files from. The C-200 can play BD-ISOs with BD Java content.
The small one, the A-200 could only be stocked with one SATA HD, and can play the same formats as the big boy, but It has no license to use BD-Java. So BDs with Java Menues ust play the main movie, and have no possibilities to use the extras. Language Settings can be done by a player menu.
To be honest: at the moment the popcorn hour is quite expensive and there are some important things that don't really work fine with the current firmware.