First Part: Back Cover deffect (could note it at home only,since it's very small, but it costs you around US$300 do fix it)
My first iPhone had a back cover deffect, near to the camera lens. THen, I went back to the Softbank store (iPhone reseller in Japan), and complaining. THe first answer was: "Sorry, we're limited of stock, so we can not fix it now, nor replace it". Then I asked to talk to another person, and I complained again. After a lot of discussion he had agreed with me about the manufacture defect, and told me the thrue, 30.000ens (around US$300) will be need to fix it, and finally they replaced my iPhone.
Second part: (slow OS)
I saw differences between my first 3G iPhone and my second 3G iPhone. Besides the back cover defect, the first 3G iPhone I had was freezing a little, so my old iPod Touch OS was more fast. Even scrolling through my Contacts, was freezing a little in my first 3G iPhone. I had reboot it and it still keep freezing. I thought it was normal, since there's a phone running, thus slower then my old iPod Touch. Now that I got my second 3G iPhone, the OS is working as fast as my old iPod Touch. It's very strange to have this kind of differences... I pay one cent that Apple have quality control hardware issues right now, since its production is in a high level.You should pay attention about this details and if you see troubles, go to the store possible before the replace warranty expires.
My first iPhone had a back cover deffect, near to the camera lens. THen, I went back to the Softbank store (iPhone reseller in Japan), and complaining. THe first answer was: "Sorry, we're limited of stock, so we can not fix it now, nor replace it". Then I asked to talk to another person, and I complained again. After a lot of discussion he had agreed with me about the manufacture defect, and told me the thrue, 30.000ens (around US$300) will be need to fix it, and finally they replaced my iPhone.
Second part: (slow OS)
I saw differences between my first 3G iPhone and my second 3G iPhone. Besides the back cover defect, the first 3G iPhone I had was freezing a little, so my old iPod Touch OS was more fast. Even scrolling through my Contacts, was freezing a little in my first 3G iPhone. I had reboot it and it still keep freezing. I thought it was normal, since there's a phone running, thus slower then my old iPod Touch. Now that I got my second 3G iPhone, the OS is working as fast as my old iPod Touch. It's very strange to have this kind of differences... I pay one cent that Apple have quality control hardware issues right now, since its production is in a high level.You should pay attention about this details and if you see troubles, go to the store possible before the replace warranty expires.