Have a look at https://hub.libre.computer/t/distro-support-list-for-libre-computer-boards/27 and https://hub.libre.computer/t/best-os-to-get-up-and-running-with-aml-s905x-cc/250
If you want something closer to the standard Raspberry Pi experience, Raspbian: https://hub.libre.computer/t/raspbian-11-bullseye-for-libre-computer-boards/82
If you want a more “standard” Ubuntu experience, Jammy Jellyfish 22.04 LTS https://hub.libre.computer/t/ubuntu-22-04-1-jammy-lts-for-libre-computer-boards/20
People also seem to be playing with Armbian, LibreElec/CoreElec/Lakka and others… but the main 2 seem to get the most use and are a good, stable, supported starting point.
GPIO pin control is a little different, and RPi startup text config files not being used are the big differences… some HDMI screens with less-common specs have been reported to not work properly but I’ve had good luck with the ones I’ve tried. If you follow the Libre install guides (note power requirements and SD card quality/imaging tool suggestions) you’ll get a working system that behaves like a normal Linux system. @Librecomputer is quite responsive to questions if you do run into problems.
Overall, I’d characterize it as “similar” to a Raspberry Pi, and capable of doing most of the tasks that a RPi can do, but don’t expect it to be a direct drop-in replacement. I’ve seen people using it for 3D printer control with Octoprint/Klipper, emulation with RetroPie, ad blocking with PiHole, automation with Home Assistant and just general desktp/server use for programming and such. I haven’t had any major problems with mine.
Enjoy!