[noggin]

I think if you are looking for a Dolby Atmos or DTS:X playback solution and have a suitable speaker system - you are probably able to stump up for a slightly higher cost player than the £30 Pi 2... A Chromebox will give you HD Audio bitstreaming (so deliver Atmos and DTS:X) - though the Pi 2 is the only real solution for internal MVC playback (albeit rewrapped in MKV).

You're probably still stuck with an external Windows solution for 3D ISO playback, and probably best off with a Core i3/5/7 GPU for it...

The Pi 2 is incredible value - and getting HD Audio (albeit decoded to PCM losslessly in the case of DTS HD and Dolby True HD) and 3D Framepacked output of MVC content for the money is pretty awesome...