This is just my experience with Miracast in general on Windows Phones (pre-950) and Surface Pro 2:
The Fire TV Stick is the worst implementation of Miracast I've seen and doesn't work on many devices. (For what it's worth though, its interface and apps are far better than the Roku, and it is still my streaming device of choice.)
The Microsoft Wireless Display app on the Xbox One is pretty bad too, but a little better than the Fire TV and works with more devices.
The Roku Streaming Stick is decent at it.
An LG Projector is average as well.
The Netgear PTV3000 was really good for its time, but is no longer supported.
The Microsoft Wireless Display adapter is really good.
However, the Screenbeam Mini 2 (I have the non-Continuum edition) is best of any of them.
One thing that has proven to be really important for Miracast, is continuous update on the receiver. The Fire TV, Xbox One, and Roku added the feature as an afterthought, haven't updated it since. The PTV3000 was great when it was getting updated, but it's terrible now. The Microsoft Display Adapter gets a decent amount of updates, but it hasn't been updated since Windows 8.1. The Screenbeam one gets very frequent updates, including a series of updates for optimizing around Windows 10.