PA is a bargain compared to NJ, while NJ is, in many counties, a bargain in property taxes compared with Taxchester and Nassau Counties in NY.
I grew up in PA, and all of my relatives live there. Ten years ago, my husband and I had to move to NJ because we couldn't afford property in PA. Even with the higher property taxes, NJ was cheaper overall.
Today, in PA, where my family lives, home values have skyrocketed, and the property taxes have shot up with them. If you live in a rural area far from employment, property taxes and home values may be lower. But, otherwise, PA is very expensive compared to NJ. My guess is most New Jerseyans moving to PA are not moving to save money because property taxes there are increasing now, too.