Well about the hardware support, i.e. the Ubuntu Desktop certified hardware list is quite long [1], and I'm quite sure there are a lot more perfectly working brands/models that are just not appearing there. I've been using a Dell Inspiron model, for 8 years now not appearing in that list as a daily driver and every major distro worked perfectly out of the box, some tweak required from time to time but that's it.

[1] https://certification.ubuntu.com/desktop