I haven't had enough experience with other systems to give a decent review. And, I am only speaking to the streaming of audio. But, I have tried Subsonic & MyTunesRSS. While they are a bit more refined than Air Playit it covers my two major concerns. Functional playback: is readily served up and shuffle plays when needed. It uses WAY LESS resources than the others: almost non existent CPU and hundreds of MBs less memory.
Also, while it seems to be abandonware it's working on OS X 10.10.2 and iOS 8.1.3.