I did a large amount of research when I was looking for a new aftermarket stereo to replace the old MCS unit in my 2000 Mercedes ML430 and glad I went with ATOTO. The unit boots up very fast within seconds, swiping between menu's and apps is smooth. I recently contacted their support team and they respond quick and are very helpful. You can tell they want to make their customers happy which is a great sign when ordering from a company based overseas.
Install was very straight forward, along with the proper wiring harness for your car installation was much more manageable than I expected - especially considering this was my first time ever installing an aftermarket stereo. Thanks to the many YouTube videos out there on others installing ATOTO A6's (similar to this unit) and S8's it was easy to follow along and match the corresponding wires.
Tested out the mic, GPS, WiFi and all items worked great out of the box. Be sure not to install the WiFi stick near metal as it can be picky with the signal. I initially mounted it on a metal plate in the dash and my signal was poor but after moving it and mounting to a plastic piece, I immediately got full bars to my home WiFi. As for the GPS, I routed it under the dash at the very top in the middle and was receiving over 14 satellites while in my garage. The mic was routed along the A pillar near the sun visor and during my test calls the receiving end was able to hear me clearly.
CarPlay which I mainly use - works great and smooth. That was the main reason for buying this unit. Love how it automatically boots into CarPlay as soon as I connect the USB, no need to fiddle with finding the CarPlay app which is very convenient.
Tip for those with Mercedes W163's: you'll need to cut and sand down the previous pegs inside the dash that hold the previous radio for the dash kit to fit in. This radio has RCA cables that will fit perfectly into the ATOTO S8 so no need to cut any extra wires, just wire up the colors together and plug everything in and it will work if you want to use your stock BOSE stereo/amp (non fiber).