So I downloaded the new iOS 4 onto my 3GS and so far I love it. Thought I would play around with the new operating system before I get my iPhone 4. I'm sure on the iPhone 4, the new features will stand out even more. I'll give you a list of the Pros and Cons I've found so far. (In no particular order)
-- Folders - moving all my similar apps into folders is great. Shrunk my apps pages from 5 to 2. Just hold down on an app to make it move, move it on top of another app that you want to put into a folder with, name the folder and you're good to go.
-- Multi-tasking - sweet feature, nicely switches between apps. Double tap the home button and it brings up recently used apps. It doesn't appear that multi-tasking affects battery life but time will tell. I think it has something to do with apple using a "pseudo" multi-tasking ability. I don't think the program runs fully in the background if you're not using it. More like a "pause" feature so you can switch back and forth without losing what you were doing. If you want to take the apps out of the multi-tasking bar, just hold down the app and it brings up a minus sign.
-- Wallpaper - you can now choose your wallpaper that shows up while surfing through your apps. Nice feature, not a major update but still nice nonetheless.
-- None so far. I'll let you know what I find. Only been using the new system for a short while.
That's all for now.