Depends...Has either bike been dropped, raced, rained on, how well has it been taken care of, does the owner have maint. records for the bikes? These are the best tips to follow. Although many can just lie and say it has never been dropped or raced, or even stunted...But you have some that are honest and legit. Take a buddy or tech or mechanic with you to look at the bikes, or someone who knows exactly what to look for...It would be the best thing to do. If the bike has been raced, dropped, or stunted, stay away from it. If it has been rained on, chances are the wiring will end up going sour on it in the near future, and possibly the electrical system and electronics itself. I would say neither though. They are asking blue book on them, for the most part. See if you can talk them down. THey are probably trying to take advantage of the fact everyone is freaking about gas prices and wants to get a bike. I would say though, whatever feels more comfortable to you though.