iPhone 3GS
Roughly twice as fast as the 3G, with autofocus, video recording, a compass and Voice Control.
Released June 19, 2009 · Discontinued September 12, 2012 · From $199 (16 GB, with contract)
The S stood for speed and Apple said so out loud. The 3GS kept the 3G's case and screen and put a 600MHz Cortex-A8 and 256MB of RAM behind it, which roughly doubled how fast most things on the phone happened. Applications opened in about half the time. The camera finally grew up. Three megapixels, autofocus, tap to focus, and video recording at VGA 30fps with basic trimming on the device itself. A digital compass arrived alongside it, and Voice Control let you dial and pick music by speaking, two years before Siri. Everything else stayed where it was. Same 3.5-inch 320x480 display, same plastic shell in black or white, same $199 and $299 pricing on a two-year contract. It shipped June 19, 2009 and stayed on Apple's price list until September 2012, which made it the longest-selling iPhone of its era. Apple supported it as far as iOS 6.1.6.
Reviews & Reception
The consensus was that iPhone OS 3.0 mattered more than the hardware. Reviewers called the 3GS evolutionary, noted the speed and the new camera, and told most 3G owners to take the software update instead.
In my tests, both the new phone and the new operating system performed well, with a few small exceptions.
I believe the two strengthen the iPhone platform, make it likely the iPhone will continue to attract scads of apps, and are good for consumers.