Damn I completely forgot of I am legend and Train to Busan. Train to Busan is easily one of my favourites. As a horror movie, it doesn't go as hard as Rec, but the emotional ending literally always gets me. That ending alone is the best in any of those movies.
Even without bias, I think Rec is just really that good. It's the scariest of the bunch, since it's a bunch of people trapped in a building. Quarantine 2 is a similiar principle, but stuck in an airport warehouse place.