It's fast, pretty much the same thing as owning a Mag box tbh. It worked great in my Shield and it also works great on my Fire TV Stick 2nd Gen. You can have a great experience if you map the virtual keys to control the interface easier on your Alexa remote (I meant the red, green, blue and some other keys on the original Mag remote).

I have both and both work just fine. Not sure about your second question.

I have an issue on stbemu where changing channels automatically changes my volume to halfway.

In my testing, stb emu works almost as good as a mag in regards to the streams.

HOWEVER, setup and accessing the menus is much more complicated.

For example, the 4 coloured buttons need to be custom mapped and navigating the on screen menus are extremely difficult for non tech savvy users.

I use stb almost exclusively now for my own theatre setup, but for my family this is an absolute no go.

It loads faster on my Samsung TV than my MAG box.

On my 2nd Gen firetick stbemu did not run that great. Lots of stuttering. Plus, with shows on catchup I couldn't go forward or rewind. I just bought a shield and its been like night and day. Much faster, no stuttering, and I can fast forward/rewind catchup.

It works pretty well on amazon fire tv. It is watchable freezes sometimes though.

What's the point when you can use Perfect Player.