I own a Popcorn Hour C200 and it plays BD ISO files flawlessly. I also own a Popcorn Hour C300 and I can only say DONT BUY IT if your main wish is to stream full BD ISO's to your AV receiver, tv or whatever equipment you use.
As Syabas so kindly tells with their newest firmware (a couple of weeks ago) this release it's still unstable with BD ISO soundtracks.
The PCH C300 crashes with the sound if you play DTS Master Audio in intense movie scenes and it doesn't matter if you stream from a network, USB drive or an internal harddisk. Lot's of ISO's it cant play at all.
The same ISO's play perfectly on my PCH C200 and my Oppo BD-P93.
I Wouldn't be surpriced if their is a flaw in the Sigma chip since Syabas seems to be unable to fix the problem, they normally do a great job with releasing new firmwares, solving problems and adding new features.