Switched to an XPS 15 and have been very happy. Love the build quality, specs are good enough. Battery life is much better even on Linux.
YMMV!
I had a number of issues with the Thinkpad that were all relatively minor in and of themselves, but overall, I ended up switching back to the XPS 13, and I plan on sticking with this line.
The Killer wifi has been reliable for me, IMO atheros or intel is always a good choice for wifi on linux
Coil whine, stability and WiFi (terrible at first) have improved after some BIOS updates this year. Also my trackpad has stopped rattling, probably dirt got into the gap and plugged it.
Dell customer service experience was also poor when buying. Next laptop I'll be going back to Lenovo.
I'd rather get a laptop with no branding at all, but the Alienware logo is at least really small. (And the keyboard on the Alienware 13 is good, my brother has one.)
I'm still looking for the perfect replacement for a MacBook Pro. Hopefully when the 2018 XPS 15 comes out...
https://certification.ubuntu.com/hardware/201702-25371/
They are rugged and have a good keyboard. You can find a brand new at 70% of a Dell XPS price (at Lenovo's outlet / eBay / BHPhotovideo).