The truth is that the 4S brings healthy improvements to an already excellent device. iPhone owners finally get a 64GB model and a better camera, the dual-core processor delivers more speed, and Siri, the iPhone 4S' personal assistant/robot friend/gofer, adds a new and sassy experience. iOS 5 also trots out changes big and small, and we're glad to see Sprint join the Apple family with a true world phone. So while the iPhone 4S isn't the Jesus phone, it's quite enough for plenty of other people-- more than a million, actually.
Not everything impressed me. I'd prefer a slightly larger screen and my list of iPhones misses remains hefty. Verizon's network delivers satisfying call quality and data speeds, which were comparable to its iPhone 4. Big Red's 3G network is faster than on Sprint's in our tests, but Sprint has a slight edge in overall call quality. Remember that there will be a discernible difference between the 4S versions (just like we found with the AT&T and Verizon iPhone 4S) so it's important to choose your carrier wisely.
In the end, the decision to buy an iPhone 4S will depend on your current carrier contract. If you aren't eligible for an upgrade with a rebate, I don't think the new features are worth paying full price (at least $500). But if you can upgrade with a discount, or if you're a Sprint customer waiting to get your hands on the iPhone for the very first time, there is enough here to warrant a switch. Sure, there's the chance that a better "iPhone 5" will come next June, but that's a long time to wait. Besides, in the cell phone world, something better is always around the corner.