I ran the HTC Vivid, Samsung Galaxy S II Skyrocket, and iPhone 4 through some SpeedTest.net paces. The findings were strange. The Vivid absolutely slaughtered, with an average downstream speed of 19.6 Mbit/second, upstream of 12.6 Mbit/second, and a decently low ping of 75 ms. That's damn good for a phone, besting a lot of dedicated residential connections, and enough to download a full song in a couple of seconds. It's Verizon-good.
The Skyrocket, on the other hand, was not an afternoon delight. It was a complete dud, in fact, showing an average down speed of 3.95 Mbit/second, up of 0.94 Mbit/sec, and a painful average 316 ms ping. That is awful latency.
By comparison, my iPhone 4 pulled average speeds of 3.79 Mbit/second down, 1.3 Mbit/second up, and a ping of 93 ms. In other words, better than its LTE rival. Something's not adding up there. Now, this test was far from comprehensive, and it's possible the Samsung was having trouble interfacing with the new network, despite indicating that it was indeed locked onto an LTE connection. So what gives? I don't know. I'm willing to chalk it up as a fluke or glitch unless I hear reports of the same.
What I do know is that AT&T's stab at LTE is killer from day one. A major caveat, of course, is that there were very, very few devices taxing that LTE network in DC that day. On the other hand, AT&T hasn't had the chance to beef up and fine tune the network in response to inevitably heavy traffic, either. Ultimately, we're seeing true broadband speeds via phone. Not marketing hype. Data that will make your pants hot, snatch Netflix in an instant, and breeze through maps. It was a little hard going back to that iPhone.
Note: All above data is the average of ten indoor tests conducted from the exact same location, during the same timeframe, in Northwest Washington, DC, via SpeedTest.net.
Update: AT&T checked into the molasses Skyrocket speeds, and confirmed there was a SIM card problem preventing the phone from getting an LTE connection. So, disregard those scores.