I've been using MicroG+Lineage for a few years now. No complaints from me, but I don't use a ton of apps. Not sure what the advantage of CalyxOS would be over my current setup (especially considering Lineage has a much better catalog of supported devices)
If you are not using root, CalyxOS lets you relock your bootloader with the developer key, which increases the security of your device by preventing other operating systems from being booted or flashed onto your device (until you choose to unlock the bootloader again, which requires you to enter your lock screen password and would wipe the device data). CalyxOS only supports devices with bootloaders that can be relocked with a custom key.