Apple definitively has a problem here.
I recently upgraded my IOS from 8.1 to 8.4 and airplay to play music is a fiasco. It connects but after a couple of songs it disconnects. I am using the same wireless set up from my computer without any problems. Since I use this feature quite a lot I wanted to make sure, I downgraded my IOS back to 8.1 (I always archive a backup before an upgrade) and the problem is resolved again. It works fine with 8.1 (though not perfect as some times it does not see the device to connect, but once it does, it STAYS connected, vs with 8.4 where after a song or 15 mins it reliably disconnects).
Apple please fix this.
My set up is a Yamaha Receiver connected via ethernet to a NetGear router. Both MacBook Pro and Iphone connected wireless. (Yes even without the apple devices, 8.1 works fine... 8.4 does NOT), could be the music app, or just the IOS dont know but since they come together to me its the same I have to keep my iphone on 8.1 until apple recognizes they have a problem here.