Good experience for me.
I have had the GA5166F Android 4.4.4 unit for over a year now and all has been pretty much spot on.
I had business CD and no DSP, so install was straight forward, after cutting out all the dash mounting brackets etc.
All works as expected, apps download and work well.
Slight adjustment to the lighting color and it is an exact match to the dash.
Radio is good, sound is impressive (I do have after market speakers and a sub).
I've retained the MID in the glovebox, so all log features still work.

I had to do one factory reset over a year and reinstall everything, but that was the only glitch I have had.
One thing I don't like, is that I can only control volume from the steering wheel in third party apps. I might be able to set this up, but it's not obvious on how to do it.

I have thousands of songs running off a micro usb card and use it daily.
For me, it has been a great unit and unbeatable for the price.