There's two things you want: 1. To know that every feature of the laptop should work out of the box. 2. Ongoing hardware support. You don't have to keep th

There's two things you want: 1. To know that every feature of the laptop should work out of the box. 2. Ongoing hardware support. You don't have to keep the supplied OS if you don't want to but what you want is support. As long as it comes with Linux pre-installed the manufacturer will put resources into ensuring it works or you could return it. That's not the case if you just buy a Windows laptop and wipe it.