There are many different models/configurations of ThinkPads so there is no real answer to your question unfortunately.<p>Purely anecdotal, but I've been using a T450s for over five years and I don't see myself really upgrading anytime soon. If I do upgrade, chances are I'd get another ThinkPad. I like how little they can cost and how they don't conflict with Linux.
I recommend the thinkpad t or x series over the dell xps 13.<p>- XPS 13 is going to look way better, have better screen. But
- Thinkpad, more comfortable keyboard, more ports, you don't mind throwing it around, and it's cheaper.<p>You can currently get a Thinkpad x13 AMD for about $750, tax included and it'll do all you need, minus playing games.
I got the Dell XPS 13 with Tiger Lake (non-developer edition) and while it's very good, I dislike the lack of more than one USB port and Ethernet. It worked fine on Linux, but it required a recent Kernel for the distro to find its disk.<p>I don't know what comes with the Thinkpad you're looking, but make sure you get one with the newest Tiger Lake graphics, it's significantly better than Ice Lake and miles better than the 14nm stuff.
Assuming you’re considering a modern Thinkpad, I’d say Dell because Lenovo has been caught installing malware on their laptops. Dell has also explicitly supported and preinstalled GNU for longer (although they don’t necessarily contribute to it as much as eg. Purism with PureOS or System76 with pop!_os, but they have upstreamed drivers for their privacy features).
I've used both.<p>I did a trial with a T490s and settled on it. The keyboard is better on the ThinkPad and it doesn't suffer from the heat problems and screaming fans of the Dell XPS 13.