I've had a dell precision 5520 for several years now. Its been solid from a software support standpoint. Downside is the stock batteries swell up; I've settled for lower-capacity aftermarket batteries instead. On my second keyboard, second charge port and second power supply. Unfortunately a screw fell out and then the hinge broke as a result, and charging has gotten wonky, maybe since the charge port's attachment point broke too. If you put the charge cable in just the right place it'll charge, but sometimes I can't find that position.

Pluses:

• 32g ram
• nvidia graphic accel
• replaceable keyboard, battery, memory
• touchscreen, webcam, etc all work.
• high dpi screen
• good linux support.
• daily driver for 5+ years

Minuses:

• USB3 dock doesn't charge enough, still needs power supply.
• front edge of the laptop is a bit sharp
• swelling stock batteries, keyboard and mouse gradually stop working.
• should have used locktite on screws, some fell out and now hinge, power wonky.

I also have a thinkpad w520. Super solid, but gets hot when the gpu is enabled. Probably needs a thermal paste refresh. Still on the original keyboard. On second power supply, first one's cable is getting sparky. Slow compared to the dell, short battery life, very heavy, still working though!