If you are happy with the audio being resampled 44.1k -> 48k https://discussions.apple.com/thread/2715198?start=0&tstart=0
And issues with the optical out put https://discussions.apple.com/thread/3789959?start=0&tstart=0
And the firmware updating not working for non obvious reasons ... http://www.zdnet.com/the-incredibly-annoying-case-of-the-apple-tv-update-7000008387/
Then knock yourself out.
its fine for its intended purpose, less so for audio.
You might consider the raspberry pi for such duties. It too is a work in progress
Some people have used it as a (n underpowered) LMS Server
Or more reasonably as a client (with external usb dacs, but there seem to be issues with the pi's USB audio / Stack)
and then packaging it up in a retro form factor
The hdmi interface (for audio output) does not seem to suffer from these issues ... (search for squeezelite , raspberry pi, HDMI audio output)
We live in interesting times for cheap, capable, streaming audio transports / clients.