Got it yesterday on my 60th. Then the fun began, as I started to f**k with it. So here is what happened:
1) Booted it up, and everything worked great. Pop OS sucks. So I shut it down to begin the surgery.
2) Opened it up which was agonizing since to remove the bottom plate, you have to (gently) remove the keyboard(!) in order to get the bottom cover off. Finally managed to get the darn cover off without breaking anything, or fubaring the ribbon cables underneath the keyboard. Removed the three screws and flipped it back over. Removed the cover, pulled the 8gb stick of ram out, and inserted the two 16gb modules (32 gb yay!). Removed the WD Green 240 gb SATA SSD, and replaced it with a 500 gb Samsung 970 EVO Plus NvME drive. Reassemble.
3) Insert Mint 19.3 flash drive, power up.
4) Install Mint, seems ok, hmmmm no WiFi recognized, funny it was there under POP OS.
5) Reboot after installation of all updates, get a nag screen to recover Pop OS, slow boot. Mint finally comes up, no Wifi, at all. Walk upstairs and hook it up to ethernet, that works.
6) Install System 76 PPAs, reboot, get message NO OPERATING SYSTEM FOUND. Reboot, get same message.
8) Make a POP OS 18.04 LTS flash drive, insert it, machine refuses to see it. No joy.
9) Cuss and rage quit.
10) Calm down, and make a POP OS 19.04 flash drive.
11) Insert it into the same USB port, no joy. Put it in another USB port, IT IS ALIVE!
12) Install Pop OS.
13) Update, learn rapidly that Gnome and especially POP OS version of Gnome SUCKS @SS. I HATE IT. I want my Mint back!!!!
14) Research- discover that I can install Cinnamon, so I do so. A normal desktop arrives, but I still want my Mint back, even though I have no wifi.
15) Boots really slowly for some reason. Maybe Coreboot?
Some positives: The keyboard is great. The build quality is really good, LOTs of ports.