For me, I had requirements that were previously met in the MBP: good battery life, good processing power, and not too bulky. I didn't really care about camera or touch screen or fingerprint reader. Based on this, I finally found the Dell Precision 5520 which is the workstation version of the Dell XPS 15". Everything was configurable (OS, CPU, GPU, RAM, battery, screen) and with a good build quality and small form factor. Ubuntu 16.04 LTS was an option, meaning drivers were configured and supported by Dell – a relief, after some experiences using Linux on laptops years ago. Now I've changed the OS to Manjaro, added a 2nd RAM stick for a total of 32GB, configured a bit the power settings with `powertop` and I'm really happy with my portable powerhorse lasting >10h when coding.
As for the Dell client service, I happened to use it a month ago because my 2 years old battery was now swollen. As I took the 3-year warranty extension "Next business day", I called on Monday and Tuesday the technician was there to change battery and touchpad (that can sometimes break when the battery swells) and it was all. Fast and convenient !