RAGBRAI and PBP are two totally different kinds of rides.

RAGBRAI is what you make of it. You can get up early and ride the route with the families and more serious riders. Or you can get up at noon and ride/drink with the party riders. Or anything in between. Prepare to be ripped off on RAGBRAI. Every vendor way over charges for their crap. I recall spending $7 for a corn dog and $5 for a shower. It is a lot of fun though, just bring spending money.

PBP is a more serious venture. 1200km in 90 hours. Not really in the same league as RAGBRAI. But I did have a friend at the bike shop ride it this year and he loved it.