Bro its always better to move back or lean out of the way. your body still takes some of its forced even if correctly blocked. but the big reason is this, when they throw a big punch and miss it takes them more energy than throwing it to stop it and avoid your counter.
moral of the story only throw monster punches if you can hit them and avoid getting hit hard by counters.
If a law is unjust, a man is not only right to disobey it, he is obligated to do so. ~ Thomas Jefferson