Well, after using the Iphone 4 for a few months, I have come to a conclusion that I need the Morphie Juice Pack Air. I am saying this is because I can't bear to charge the mobile device every night! Sometimes I might forget to charge it and I will have missed calls or e-mails and so on in the morning. This is not good at all!
Apple has mentioned that the iOS 4 meant to provide multitasking without much drain on the device's battery. However, I can safely say that multitasking does a massive power drain on the battery. In doing so, the Morphie Juice Pack Air is the best candidate to supply me with another days' juice without charging.
Having said that, I went to many Apple stores and they don't stock Morphie Juice Pack Air for the Iphone 4! They only have stock for the 3G and 3Gs! What is going on withe you Apple? You don't have stock for the Iphone 4? How disappointing!
The only consolation which I have from using the Iphone 4 is that it runs very well with the equipments at work. I am still waiting for the N8 to arrive. I hope that I will be able to get my hands on it very soon!