7 sourced reports, with what to check before you buy. Each one links to the page it was reported on.
Costly or dangerous
XPS 13 7390 2-in-1 suffers daily blue screens
An owner of the XPS 13 7390 2-in-1 reports daily blue screens from day one, with Dell diagnostics finding no hardware fault.
What to check. If you buy a 7390 and see repeated BSODs, push Dell for a resolution early; the owner was told software issues are not covered under basic warranty.
XPS 13 display fails via eDP cable/hinge fault when lid opened
An owner's display blanks as the lid is opened past one-third and then fails entirely while an external monitor works; the diagnosis points to a display cable/hinge fault rather than the GPU.
What to check. If the screen cuts out when the lid is moved, suspect the eDP cable routed through the hinge; repair involves replacing the cable/panel, typically out of warranty.
An owner of a high-end XPS 13 (€2,518) reports severe overheating that forced a fan replacement, yet the machine still runs excessively hot afterwards.
What to check. Check thermals early; if the unit runs hot even after a fan swap, expect recurring overheating and treat it as a persistent design weakness.
Dell support refuses help on XPS 13 7390 unless extra support purchased
Dell told the owner the BSODs were a software issue and would only help if they bought additional support, since software is not covered under the basic warranty.
What to check. Confirm what the warranty covers for software/firmware faults before relying on Dell support; basic plans may exclude software troubleshooting.
XPS 13 cooling fan loosens and scrapes against aluminium chassis
A company running Dell XPS units reports the XPS 13's fan loosens and scrapes against the aluminium housing, a recurring hardware noise/vibration defect.
What to check. Listen for fan scraping/rattle early; a loose fan rubbing the case can precede fan failure and needs reseating or replacement.
These reports come from the pages linked under each item: owner forums, repair guides and workshops. They are not a diagnosis of any one unit, and a careful check of the one you are buying still applies.
Text from the Kriko Laptops catalog, version 0.1.1, under the CC-BY-SA-4.0 license.