I tested the Samsung Galaxy S II in San Francisco using U.S. Cellular's roaming network. Call quality was pretty good overall. Volume sounded fine to my ears, though voices were slightly robotic around the edges, and I did hear a few blips. There wasn't any additional background noise, though, and distortion remained mild. On their end, callers said I sounded a little hollow, but generally good, and with strong volume. At higher volumes, my voice reportedly sounded a bit distorted.
Samsung Galaxy S II (U.S. Cellular) call quality sample
I tested speakerphone by holding the GSII at waist level. As soon as my caller started talking, I had to crank up the volume to hear. Even though voices were louder, they also sounded more echoey, hollow, and buzzy. For their part, callers were pleased with the speakerphone quality. They noted that they could still hear echo, but not at volumes that surpassed the normal amount that reverberates around the room. They pronounced my voice clarity "clear" and "pretty good."
To test out U.S. Cellular's 3G network speeds for the handset, I downloaded the diagnostic app Speedtest.net. Data speeds hovered in the 0.23Mbps and 0.37Mbps range, not very impressive. In real life, page load time was acceptable for 3G--roughly 15 seconds for a mobile-optimized page and 30-60 seconds for a much more graphically rich site.
At $130, the Samsung Galaxy S II is officially U.S. Cellular's priciest phone. It's also its best, and its flagship, and the one I'd recommend in a heartbeat for customers of the nation's sixth largest carrier. Even as the next wave of superphones begins to flood the market, the Galaxy S II is a handset that can go the distance. The only caveat is that U.S. Cellular is planning to build out a 4G network, and when it does, the GSII won't be able to access those faster speeds. If you're a current customer with a good chunk of time left on the contract, it could behoove you to wait for LTE.