Just took a drive.
The Good:
It's Google Maps, works the same way as on your phone, smooth and responsive, colors and detail all the same. Best of all you get the little speech bubbles telling you that if you take the Long Island Expressway instead of the Northern State Parkway it's 2 minutes longer *during* turn-by-turn navigation. No need to back out to an overview like so many other apps do. This is worth the price of admission alone. I'm glad this killer feature was not removed.
The Bad:
CarPlay integration is an afterthought. You can't ask Siri to "take me to Starbucks" as that will launch Apple Maps, there is no way to make Google Maps the default. You can use voice once you're in Google Maps but it requires scrolling to (or touching on) a microphone icon that's in a submenu and not easy to find and not quick to get to. As a result of all of this, its downright difficult to enter an address where it's super easy with Apple Maps.
In my 2018 BMW, disappointments lie within the iDrive system, when you choose the option to "Use Maps In CarPlay" it only launches Apple Maps, there is no option to launch Google Maps instead. My iDrive controller has the ability to accept handwriting, but handwriting does not work with Google Maps. Perhaps BMW will make a future update to provide these nuances. Perhaps it's Apple's decision.
So it's great to have Google Maps on a large screen and it's great to get those speech bubbles as you drive on a highway using turn-by-turn. But it's an orphan app as far as CarPlay and the OEM navigation is concerned with no Siri possible and no shortcuts allowing a launch straight to Google Maps, Apple Maps being the default and taking the convenience all to itself.