I've heard decent things about the HP Spectre, but it was fairly new, either a 2016 or 2017 model. Some minor quirks with Ubuntu and older kernels, but I think they got 16.04 or 16.10 working well.
Sounds good. Spectre 360 looks as nice as the Dell XPS, if not better.
I also think they are a bit cheaper, but I'm not sure about hps track record regarding quality and Linux support.