Sleep kind of sucks on the original 11th gen hardware. They pushed out a bios update that broke S3 sleep, so now all you've got is the s2idle version, which the kernel is only OK at. Your laptop bag might heat up. S3 breaking isn't really their fault, Intel deprecated it. Still annoying though. I've heard the Chromebook version and other newer gens have better sleep support.
Other than that, it's great. NixOS runs just fine, even the fingerprint reader works, which has been rare for Linux
Couldn't tell you unfortunately. It looks like AMD is also on board with deprecating S3 sleep, so I would guess that it's not significantly better. The kernel controls the newer standby modes, so it's really going to depend on how well it's supported there.