Early Impressions of iOS 4 Performance on my iPhone 3G

I am finding the performance of iOS 4 noticeably worse than OS 3.1.1

I often come across delays where there should not be delays. This is not entirely new: it happened with past versions of the OS but nowhere near so often.

When the phone is locked, there is sometimes a delay between pressing the home or lock button and when the screen comes on. Also screen often freezes for up to about three seconds when sliding the unlock slider. This seems unpredictable and is annoying when trying to 'quickly' check something on the iPhone.

The zooming animation when launching an app is faster. I don’t think this help for most apps as they still have to load, but it speeds up launching apps that run in the background, such as Safari.

Apps sometimes take a very long time to load. On two occasions, I have seen apps fail to load and was taken back to the home screen from the 'default PNG'.

The animation of quitting an app seems to be slower. I can see the home screen icons moving into place, which did not happen before.

When you take away multitasking, there are still many smaller new features and improvements in iOS 4. However, with the significant degradation in performance I observe, I think that, for me, iOS 4.0 may be worse overall than OS 3.1.1. Since I have only had the update running for a couple of days it is still early to be sure.