I have owned every iPhone up to the 3GS (soon, the 4th iPhone) and I have jailbroken each device, each time giving it "another chance." About a month after each time I jailbreak it I restore because of the poor performance and battery life. It makes the phone so much buggier, and technically is illegal. It's a plus to those who don't jailbreak to get updates w/o having all the data deleted from your apps. There's a reason Apple doesn't allow it.