I have the XPS 13 Dev Edition (9310, from mid 2021) and replaced Ubuntu with Arch Linux.
1. The fingerprint reader needs some older and/or patched versions of the corresponding tools/daemon. I fixed it upon setup, but don't really use it so didn't bother checking if this works now with the latest vanilla versions.
2. Something related to Bluetooth causes random CPU lockups (I think the kernel/driver is the culprit), so I have it disabled.
(3. IIRC the Wifi wasn't properly supported by the mainline kernel for some time upon release - but I bought the laptop quite late into the product cycle, so this didn't affect me)
4. The WiFi chip does not support promiscuous mode
If it was really as Linux-compatible as the ads suggest, everything would work out of the box with mainline kernel & upstream versions of user-space tools.
Mostly they probably should have picked a better supported WiFi/BT combo chip (e.g. something from Intel) instead of using a chip that barely works (yes, it's soldered on and I the dev variant probably has the same PCB as the non-dev variant).
Besides that, the UX is quite good. As you say, sleep works well (but I'm expecting that from any decent laptop; I know, I'm expecting too much). The touchscreen is awesome in Chromium (too bad Firefox doesn't touch-scroll, but maybe that can be reconfigured in about:config).
[edit] light rephrasing, added 4. + last two paragraphs.
