I am a pinner. It works for me and makes me a better sewer.
However, one must remember what else helps squares to line up like we want them to and that is cutting those little buggers accurately.
Always use the same ruler to cut all your pieces for a project. I always use the same rotary cutter too and make sure the blade is sharp. Put markers on your rulers so all of your squares are measured the same.
Luckily, I have not had a problem with my squares not aligning properly.
My motto: measure twice then cut once.
Good Luck!
Chris