iOS 7 tosses out the old ornamental, object-based design in favor of a a flatter interface that is "much more intuitive," according to PC Mag, and IGN says that "navigating menus and making selections is more streamlined." With the new Control Center, users can now "swipe up from the bottom of the screen, no matter what app you are in, and get easy access to specific settings," says ABC News, and TechCrunch calls it "incredibly useful." There have also been changes to how iOS 7 handles multitasking, and core apps have been redesigned to match the new aesthetic, but overall, it "isn’t a big change functionally from what we’re all used to with iOS 6," according to the Loop. Users who pick up an iPhone 5s (or 5c) will get iOS 7 automatically with their device, and Forbes feels that "iOS 7 is, in many ways, an advertisement for the iPhone 5S."
But, the decision to upgrade is not so simple for users of older devices, with Forbes also noting that "animated transitions sometimes stutter on the iPhone 4" and AnandTech finds "performance however on the iPhone 4 and iPad 3 leaves a lot to be desired." If you upgrade to iOS 7, you'll be trading speed for convenience, which is worth it for some users but, for others, may be a reason "not to upgrade immediately," says Macworld. However, the tradeoff is also not a reason "not to upgrade ever," since Macworld also notes that "as third-party apps start to be built around its new capabilities and embrace its new design, I think there will be even more to recommend it to users." Gizmodo says, "if you like your iPhone just fine the way it is, you might want to wait." Just don't wait too long.