The iPhone 4S hit stores today, now being offered through AT&T, Verizon, and Sprint. The phone is identical on all carriers with each having to differentiate based on other factors like network speed, reliability, customer service, and data plan terms. If you’re still undecided about which carrier and network speed is key to your decision, then definitely check out this speed test video of all three iPhone 4S models side-by-side after the cut. AT&T has been touting that its iPhone 4S will be the fastest because the device supports the carrier’s HSPA+ enhanced 3G network, whereas on Verizon or Sprint, you’d be getting just standard 3G speeds. But in the below video, you’ll see that Verizon and AT&T are neck to neck with Sprint generally behind. However, the SpeedTest.net comparison shows AT&T way ahead with a download speed of 0.65Mbps, Verizon with 0.26Mbps, and Sprint with 0.16Mbps. The tester claims that the results were similar no matter how he arranged the posit