I'm still using my decade-old Precision 5510 (the XPS 15 at the time was a variant of it), and I've rarely felt the need to replace it, beyond Nvidia no longer supporting the discrete graphics as of last year.

There was a period around Project Sputnik where they were making really good machines. Years of abuse, and it's still in good condition, though the battery has been showing its age lately.

It's rather sad that things have gone downhill since then, as there was a period there that Dell were really good.