One of the things that concerned me with the iPhone 4 was the larger pixel size camera. I really love the Hipstamatic App but the processing is slow and leaving the App loses the image. The 4 has more pixels but the processor is faster it seems to even out but more importantly it will multi task. So after I take a Hipstamatic image I can go on to do other things and it still works the image in the background.
I did find in initially that my Hipstamatic images had motion blur. I'm not sure why that is. I hold the camera more carefully now and the problem is gone but I will still rush and ruin images from time to time.