Another iOS4 review, this time from Ars Technica

iOS 4, previously known as iPhone OS 4, is a major update to Apple's mobile OS which brings a handful of significant changes namely Apple's implementation of "multitasking" plus the opening up of thousands of APIs to third-party developers while the rest of the improvements are basically tweaks to existing functionality.

We'll say up front that we like the update. For iPhone 4, iPhone 3GS, and iPhone 3G users (as well as second- and third-generation iPod touch users), iOS 4 will add useful functionality that will make your device more useable than ever. There are, however, some obvious downsides, and we'll address those in this review.

Because iOS 4 is launching ahead of the new iPhone 4 (and it runs on more devices than just the new iPhone), we're reviewing it separately from the phone itself. There is some functionality that is specific to the iPhone 4, which we'll address in that review when it comes out. For the purposes of this review, though, we used iOS 4 on an iPhone 3GS the most current iPhone available ahead of the iPhone 4 launch.

  Feature: Ars reviews iOS 4: what's new, notable, and what needs work