The review below is how I felt when it was working. Unforutnately, under El Capitan, all it does is crash :(
When it starts working again, my review will return to being:
I tried the various hacks to play lossless music on my Mac like Fluke etc and none were satisfactory. Free stuff like VLC can work in a pinch, but its not optimized for performance nor sound quality (playing from memory, sample rates, processing quality).
Decibel does what it says it will do and it does it very well. Quality sound, reliable playback and the key lossless formats that iTunes doesnt support.
Whats missing? Media management. Im not looking for something too fancy, and even a hook into another software program would be acceptable. Right now, there is nothing like that from what I can see. And ripping would be cool too. Of course, if both those were added, the price would likely double.
Get it now. Its a bargain and does what it says it does and does it well. (And use an external DAC. The quality of decibel means that the weak link will be the Macs own DAC. You can still use your Macs DAC of course, but youll be even happier with something better and decibel can make use of it.)