I really liked Playnite when I discovered it, but it can be a bit fiddly or rough around the edges. It reminds me of something like MediaMonkey which was an app I used to use (and still have) to manage, tag, categorize and clean up my mp3 files.
It’s probably much more powerful, but it’s less polished, pretty and smooth.
Galaxy 2 may still be in beta, but it’s in public beta now so it’s essentially released. It’s already really polished, smooth and just all around nice to use. (in most areas, a couple of stores need you to install plugins from github, which is a bit more technical).
As an example (last i checked), I have a few games on several store and playnite just puts 3 covers next to each other. Galaxy just has one cover, but when you mouseover it it shows a subtle Stack and also the icons of each store and lets you choose which to launch.
If all you want is to have one nice library to see all your games from every service / launcher and launch them then I’d go for Galaxy. It can do more than that, but that’s its current strength.
If you want to mess with things like game metadata and importing genre tags from Steam or Wikipedia or Imdb so that you can have a much more searchable library then I’d go with Playnite.
I really liked Playnite, but I was considering uninstalling it now i have Galaxy 2, which should say something. Now I’m undecided as I really liked having all the games in my library tagged with different searchable keywords.
The new steam client has also finally updated to do this.
So, basically Playnite was the answer to my prayers, but I may discovered it too late.