I looked at these several months ago and unfortunately recommend neither. Pearl's Causality is very dense, and not really a good introduction. The Primer is really egregiously riddled with errors; there seems to have been some problem with the publisher. And on top of that, I just found it not very well written.

I don't have a specific recommendation, but I believe that at this point there are a bunch of statistics textbooks that competently discuss the essential content of causal modelling; maybe check the reviews for some of those on amazon.

Causal Inference in Statistics (pdf) is much shorter, and a pretty easy read.

I have not read causality but I think you should probably read the primer first and then decide if you need to read that too.