I just received my RodeLink Filmmaker wireless audio recording system. I plugged it in my Sony a7ii and shot a few YouTube videos to see how it goes. This is definitely better than the Sony ECM-W1m® wireless audio system. It is larger and requires an audio cable to be run into the input mic port on the camera. I know without a doubt the sound quality is better and the ease of setup is just as easy. My only complaint this early in the game is I cannot use it with my a6000 unless I use my Atomos Ninja-2 external recorder. Not a deal breaker for me.
You can watch the very short video I recored here and let me know what you think about the audio system.
https://youtu.be/jUWv3jIVSlM