I remembered late last night that I could upgrade my 3GS to the new operating system version that allows multitasking among other things. So that meant I had to stay up to install it. And now it means I’ve spent a little amount of time to tell you what I think so far.
Multitasking is just OK — but it’s probably not Apple’s fault. You really need an iOS 4-ready app to make it work right. If an app is ready, it will save its complete state when you switch, so when you go back you don’t lose any data. But if it isn’t, the app’s behaviour may be unknown. For example, if you’re viewing a drug in Epocrates and switch away, the app will take you back to the start. PubMed on Tap will remember the search you completed recently, but not the article you were viewing.
As for the other features, there are a couple handy improvements. Though it doesn’t come on by default, the messaging app will now count your characters for you (go to Settings –> Messaging to turn it on). The camera will now zoom (tap the screen. Sweet). A unified inbox in the mail app will probably help for institutional users with mutiple accounts (though now I forward everything through gmail anyway…).
IMO the best immediate improvement to iOS 4 is the ability to put apps in folders. It even names the folder by default based on the type of apps you put in it (i.e. when you drag one game on top of another to make a folder, it knows). You can change the name, of course, to anything you want. I’m a neat freak, and I won’t lie to you, having all those apps scattered around everywhere with nowhere to go bothered me. Now I can just get upset about how there’s a max of 12 apps in a folder…
Overall, definitely a welcome upgrade with some excellent features. And as more apps upgrade to fast-switching it will get even better (and once Pandora comes to Canada…)