I like the fact that the S4 is slim and that its magnetic setup makes for a quick in-and-out. I also like how the speakerphone houses a dedicated sliding on/off switch at its side. (The rest of the device's controls lie below a smooth surface--it lacks physical buttons.) But the big attraction for me is its "hands-off" orientation: The S4 lets me take care of almost all phone tasks using my voice--so I can avoid having to reach up and press any buttons at all.

When my phone and the S4 are connected, I say "BlueAnt, speak to me." It responds with "Say a command." From that point on, I can use one of a bunch of preset commands to make calls or find information. I was able to call contacts in my phone book. And I found that I used the commands regularly, saying "Call back" to dial the last number I received, as well as saying "Redial," "Am I connected?" or "Check battery." Saying the term "Favorites" gives you access to various types of data from Bing 411; you can say "Stock quotes," "Traffic," "Weather," and so on. That's another plus if you're into this kind of real-time access when you're behind the wheel.

The hands-off feature worked like a charm. However, the times I needed to tap the S4 turned out to be a real problem for me while driving. To end calls and adjust volume, for instance, you have to tap particular areas on the top of the device. Sure, the unit displays clear symbols above the areas you're supposed to press, but touch-sensitive controls like these take a lot of getting used to--especially when it comes to blindly controlling them by feel.

Here's one example of how many of my initial calls flowed using the S4: Halfway through the conversation, my caller's voice starts to fade, so I want to increase the volume. To do this, I need to swipe my finger from left to right across the top of the S4. I don't want to take my eyes off the road to glance up, so I try to get it right by feel alone. I miss. I flick my eyes up to find the right area to swipe again, and get it right. ("Volume up, volume up, maximum volume," the S4 confirms.) Then the conversation ends, and I want to hang up, so I tap the multifunction spot atop the unit. No response--guess I tapped too lightly. I tap again a little harder, but I miss the spot, so nothing doing. I try again. Bingo. "Call terminated," says the S4.

I go through the same process all over again on additional test calls, and even though my taps fare better, I'm often unsure, in that split second, whether I got the tap right each time.