I have been waiting for this to come out for some time. I have Gaia on Samsung. On the phone, Gaia is ok but not great, IMHO, I have the premium version. The free version is pretty useless.
The good news.
Well it is the first off-road oriented product that works on Android Auto. I had to configure AA to make it show op on the screen and reboot the phone. But after that:-
It can display state pics, and google while online and NSW, SA, Vic, and Qld sate maps. Eg Vic topo 25K and the equivalent of 250K topo as well as OSM based maps.
It shows your position on the screen and in 2D or 3D
The OSM maps are presented better than most.
The ugly
It can follow routes, but it looks like they are pre defined routes that you make, not google like left right directions. This is pretty useless. I made a route that didn't start exactly where it was and it had no idea what to do.
The map zoom button ( only one) is stupid. You press it in in in in out in in in out. Very frustrating.
You have to change the map being displayed on the phone. I can't find a way to do it on the screen.
It keeps defaulting to miles every time I start the car and connect the phone.
Downloading offline maps is clunky and only available for a few maps due to copyright.
The tracks function seems ok.
I feel I am paying for US and other country maps, that I will never use, and they get in the way.
Hopefully, it is either still buggy or I don't know how to use it properly. It has great potential.
When you read some PR, it sounds like an off road version of Google maps with voice route directions. It's nothing like that.
I have an android head unit that takes over my screen in my 200 and use Memory Maps and Google, That is 1000 times better.
As it stands, I give Gaia 4 /10. I hope it improves as it is very new.