I have a tuxedo machine. Their support is great. The “pre installed os is bad” people have no idea what they are talking about. TuxedoOS is a Kubuntu slightly modified to include their branding (wallpapers, etc) and a couple of drivers, plus their tuxedo-center app (which you can remove if you want).
Nothing will stop you from installing any other os and if you want to come back to the original OS, you can use their WebFAI and reinstall the way they did it at the factory (or pick another os from the list).
Their hardware is fine, I have a system76 machine as well and they are comparable in every aspect, considering all of them use “generic” hardware.