Pr's always help in your training. I would rather PR by doing sets with more weight. I never do 1RM.. except for the bench the other day i did. PR's get you excited because you know you are improving and getting stronger (and hopefully bigger!) It's a good motivator too.
It's certainly an ego-stroke, but I'm of the school which believes you'll be huge if you're squatting, deadlifting and benching (or incline press or dipping) a half-ton. PRs are the only way I can approach those numbers; ergo, they're the only way I can get huge.
(Well, huge-r. I'm already making Ronnie Coleman sweat :lol: )
A PR is overcoming a lifting plateau is it not? Also its the only way to make any real progress at all. Whether its a PR in size or weights,reps...Its progress