I've moved years ago from Dell to Lenovo. And specifically to professional models which come with onsite warranty.

The onsite warranty is of course very good thing on its own, but I also believe it puts pressure on the vendor to focus on quality and getting issues sorted out quickly (because doing onsite visits is not cheap). It also indicates the computer is built in a way I can also replace parts, because you can't field service a machine that has been glued together.