The only thing that it gets wrong is that it cannot restore the file created date to video. But in the grand scheme of things, that's a nit.
I've been putting off a Google photos back up for years, and this was my excuse - waiting for this issue to be resolved. But I'm being a fool, 60% compression is better than losing everything.
I have just compared originals I had which were uploaded to Google Photos vs the ones downloaded.
Visually there is a barely perceptible difference in a side-by-side comparison on a high quality and calibrated monitor. I wouldn't have noticed if it weren't side-by-side and zoomed in.
On the file size, it's gone from a 6MB jpeg down to about a 1.5MB jpeg.
On the smaller files that difference is far less, but jpegs above 3MB seem to see the biggest reduction in file size.
Thankfully I have all of my originals that weren't taken on the phone camera so I don't mind this so much as running my exiftool script over the original archive produces the same naming convention and I can merge those folders and still have the originals I care about.
Sheesh though... such a thing for Google to screw up on.
It works extremely well, and you can re-run it any time to sync new files locally too.
I used it like that for a few months before I finally installed syncthing on my phone and stopped using Google Photos altogether.
Now what I do is take photos on my phone, have them sync to a NAS. And on the NAS I used a modified version of this https://forum.syncthing.net/t/android-photo-sync-with-exifto... to build up a YYYY/MM folder organisation and move files older than 30 days from the syncthing folder into my archive. My archive is then in my Plex so it's still accessible to me.
In essence: 1) Take photo (implicit sync to NAS), 2) wait 30 days, 3) archive photo into long term directory naming convention, whilst making available to Plex and deleting the version from my phone (by deleting the syncthing version it will delete the one on the phone after 30 days too).