I haven't been using this ROM in particular but I have been using MicroG almost since its inception (without any of the official Google stuff installed) and I have to say it's a very smooth and seamless experience.
I use Whatsapp, Riot (APK from Google Play with GCM enabled), Google Maps, and a bunch of other apps that depend on Maps and GCM services and all of them work fine.
Sometimes I almost forget I don't have GoogleApps installed.
I'm using a LineageOS Oreo build on a Moto G5s Plus (replacing an iPhone 6) with MicroG and it's like night and day. Everything's ridiculously quick. I've had some minor niggles (which I put down to my lack of knowledge) but it's pretty fantastic. The only thing that doesn't work is the dual lens camera (I don't have the app from the original firmware so I only get one lens).
I'm trying to figure out how to rebuild from non-official github repos, then I'll look at setting up a proper automated build of my own.
The point is that it's entirely up to you how many google apis you want to use, and at what terms. You aren't installing an opaque google play blob as a system app.
Actually is pretty stable right now, the most important features like Google Cloud Messaging and the Maps API v2 work flawlessly. Only certain specific apps give some issues, which usually are fixed in short time.
I use Whatsapp, Riot (APK from Google Play with GCM enabled), Google Maps, and a bunch of other apps that depend on Maps and GCM services and all of them work fine.
Sometimes I almost forget I don't have GoogleApps installed.