It's all anecdotes and YMMV and all of that, but my work machine is a 15" 2017 MBP and I use it day in and day out running Xcode, Sketch, Paw, and a few other things and it doesn't crash any more often than my personal 15" 2015 MBP (which is rarely). Current uptime is 17 days, with the last reboot being tied to an update.
I suspect that either the 2017 spec bump fixed the issues present in the 2016 version or the crashes you mention are tied to specific software.
Yes, I have it plugged into a USB-C 2560x1440 27” Dell monitor all day, plugging it in at the beginning of the day and unplugging it at the end. At home I’ve also had it hooked up to HDMI and DisplayPort monitors via USB-C→ HDMI/DisplayPort cables (no docks/dongles). Neither have had a negative impact on stability.
I wish Apple would bite the bullet and release actual "pro" laptops with Xeons, ECC, and high end GPUs - similar to what it's doing with the iMac Pro. ECC would largely eliminate the need to reboot, as well as providing much better data integrity.
Late 2013 MBP here, since I upgraded to macOS Sierra, I've had crashes once or twice a week. It's gotten better in the last 2 months, so I think apple might have fixed some of the bugs.
I suspect that either the 2017 spec bump fixed the issues present in the 2016 version or the crashes you mention are tied to specific software.