I've been running Ubuntu on an LG Gram 17. Huge screen (true 17"), 18 hour battery and weighs Les than 4 lbs. It also has a metal chassis. Only device that doesn't work is the fingerprint reader.
I really like the keyboard and touchpad, more so than on a Mac (but that's very personal). The RAM can be upgraded to 40 GB, and there is a second M.2 slot if you want disk mirroring or striping.
I run Fedora and have zero problems. (I generally upgrade 3 months after a release.)
The model that I have has a 72 Wh battery and newer 17 and 16 inch models now come with an 80 Wh battery. Mine is 3 years old now and it's aged much better than I expected. I can watch a 4K movie over a network CephFS mount and after 2 hours, my battery is at 80%.
I bought it on a whim at Costco, and I seriously think I'll get another one next time (maybe a 16"). Costco drops the prices to $350-$400 off every few months, and they're a steal for what you get.