Apple networking has always been a little funky, AFP can be dodgy, even SMB doesn't always seem to work as intended on the Mac. I've had things that worked perfectly from a Windows machine but seemed to fail on a Mac. For example, my Canon printer has WiFi. From the Mac it's been a headache from Windows it just always works... of course this could be a driver issue, but restarting the printer always solved the issue.
Airplay audio has always been a little flakey with my devices not consistently showing up and even dropping out on occasion. This was with a few Pioneer A1/A3 units as well as with a Sony mini system.
I was running AirPort Extreme and a Time Capsule for my AP's, swapping those out for Ubiquity gear seemed to solve those issues (although my wife tells me the printer is playing up for her again)m but the audio stuff has been working flawlessly.
On another track, I do find that the remote app on my phone doesn't always see the ATV3 in the lounge room (which is wired). Rebooting the ATV solves the issue but maybe talks again to Apple networking wierdness.