Got my Librem 15 rev3 and am very happy with it. I saw all the versions and can say that the team has made improvements along the way with the rev3 being well constructed, quiet, fast and a joy to use. Noticeable differences include (which people are probably familiar with if they read blog posts and discussions) placement of the kill switches (back where rev. 1 had them, under the screen), black case, one SODIMM slot available instead of two (rev 1 and rev 2) and the rest you can read about (DDR4, CPU, etc.). Battery life is great.
EDIT: I forgot to mention: The laptop is very quiet!
I switched to Arch so I can’t speak to PureOS but I did get a total freeze while updating which was slightly concerning.
I recommend the laptop if you want a well constructed laptop with privacy and freedom in mind.
A happy customer.