As others have said, it varies. I prefer points, but if I don't think I'll make # of nights to get the points then 2 free nights at a Cat 1-4 beats a poke in the eye with a stick (American phrase, for the int'l folk reading this thread). I've found domestic Cat 1-4s that can be expensive that are worth using the certs for, but I realize others don't.

Cheers.