Libreboot has no binary blobs, Coreboot still has a couple. But modern CPU architectures require some of those blobs to function correctly. So Coreboot has broader compatibility with modern hardware than Libreboot.
Both are good, but I've always leaned towards Libreboot just cause I think ThinkPads from 2005-2008 look amazing and it's fun to know that there is no proprietary software on my computer.
I flash libreboot first to get rid of the intel management engine and then the latest coreboot to the bios region. I think I configuried it so that it doesn't include any blobs, but I'm not sure. Wish it were easier to tell for non-experts.
Corebooted Thinkpads are the gold standard. Don't listen to this article - it's utter nonsense - the author even recommend Libreboot which is effectively abandonware barely maintained by one unstable individual.
