I did have the motherboard die on this three weeks in, though, which has been frustrating. When it works it's a nice system, a nice counter to the trend of everything being made out of cheap plastic. You can get nicer specs for the same price but it'll be a physically cheaper machine.
I've actually had more trouble with the Windows side in terms of drivers. The parathetically-aforementioned pre-emptive replacement of the wireless was on the advice of a coworker who had trouble with the card in Windows. When you turn off the RAID so you can install Linux, the NVMe drivers in Windows become unstable. Some people apparently install the Samsung 950 Pro drivers, which can then have its own problems because of hardware mismatch; I accidentally resolved this problem by purchasing a Samsung 950 Pro anyhow. (I wanted a nice flash drive but didn't want to spend the $$$ upgrading all the other things in the pre-packaged configurations. Plus they don't say what their flash drive is, it's probably not as good.) Also it seems to help if you remove the Dell drivers for the headphone port and revert to the reference drivers, as otherwise the machine can hang when you plug headphones in under load. Which is sorta dumb. I recommend making the first thing you do with the system to build a Windows 10 install image and then make a clean install after turning off the RAID, but be sure to bundle the drivers on the Dell webpage onto the install media, particularly the wireless ones. (I didn't know this at the time, but apparently Windows 10 has licenses stored on the motherboard now, so you don't have to hassle with license keys. It just installs.) Apparently there's some way with fighting through the RAID setting change to repair the system but a clean install is nice for other reasons. (Not too much crapware, but, still.)
I will agree that the previous is a potentially frustrating set of issues for either OS for a brand new, high-end laptop. I'm used to beating my laptops into submission anyhow since I run my own quirky XMonad install and other such things, so getting this all slick was just par for the course for me. Assuming this stays working I'm quite happy with it (I'm even really liking the keyboard which a lot of people complain about, so YMMV), but it certainly could have been a nicer experience.
My "upgrade" is an XPS 9350 for 2.5x the price. Windows 10 still doesn't handle high DPI screens well, and until recent updates there were issues with the Broadcom AC wifi card. For Macbook Pro money, I expect better. There's really nowhere to go for power users who need powerful laptops under 1.5kg.
(In the market for a new laptop, and the X1 Carbon is/was on the list.)
Despite that, I am making new purchases with Dell mostly because of price and service. Check out the Latitude E7470 in comparison to the X1.
Battery life is quite poor despite considerable tweaking. Rarely get more than 2-3 hours of reasonable (low % cpu) use. Disable WiFi and decrease screen brightness and i can get 9-10 on an aircraft on a long flight. I fell it is getting worse over time too.
I've also had WiFi driver issues with suspend and resume on linux AND windows. Assumed it was just Ubuntu and their horrendous lack of QA for hardware. My wife also has the same issue on the Lenovo Yoga Pro 2 on win 10. I just rmmod and insmod the wifi kernel module to repair. PITA.
i had similar trackpad issues, these have been resolved.
Keyboard is way way too soft/shallow. Could be an issue on most laptops these days.
Speakers are on the base of the unit and are incredibly quiet. Quiet to the point where if you have a gentle breeze whip up you completely lose the sound.
Considering the cost I'm not impressed. The screen kills it for me. even glare reflecting off windows wipes it out at max brightness.
Next time I can afford an arbitrary laptop, it will me another Dell Mobile Workstation like the M6500.