In my experience they hurt equally. A charge-off can hurt more if it reports a balance as that will go against your overall utilization.
So if you have both, they are likely hurting you equally, all things considered. On the other hand, if all you have is ONE charge off and ONE collections reporting, I would probably attack the charge off over the collection, but since you can attack both equally at the same time, there's no real debate point.
I always tell people never attack either until SOL is past. I personally don't bother worrying about SOL because I can afford a lawsuit, and in both my previous lawsuits I not only won but left with money in my pocket from settling FCRA and FDCPA claim countersuits with the companies suing me/threatening to sue me. For most people who are scared to death of court (I'm not), I would confirm your SOL and don't poke any bears until its over.
