I am buying a testing device for iPhone apps. I cannot afford an iPhone 4 so I am thinking to buy an iPod touch. Can I use an iPod touch for testing iPhone apps? What will be impossible to test on an iPod touch?
My second thought is to buy an iPhone 3G or iPhone 3GS, but I am not sure if these devices are too old to use as testing devices. What do you think? Could I use them? Can a new system be installed on these devices (does it slow them down)?