I'm no expert and don't claim to be, but from what I've experienced, there is a difference. I had the pleasure of getting 6 F1's at the ACA convention auction in 97 and 4 F1's while I was stationed in Germany from 2002 until late 2005. They were the meanest and nastiest fish I have ever kept and they had better coloring as well. All the other Jacks I've had very very docile and drab in comparison. Because of reasons like this, I prefer to keep fish that are WC or F1's or F2's. This is strictly my opinion though. I have NO scientific evidence to back this up, just my personal experience.
Sent from the black hole that is my world.