I am a fan, but Brent Smith is average. I have seen them twice (should have been three times) and both times, dude failed to deliver.
First was opening for Van Halen in 2004. He COULD NOT sing, at all. I was dead center, and he ran around so much, he couldn't hit any of the notes. Hearing him gasp for air and not hit anything in "Fly From the Inside" was painful.
The second time was when Shinedown SHOULD have opened for Rob Zombie and Godsmack. They called in sick, apparently with Brent having "vocal issues. " So instead, Godsmack had Shinedown's songs, in elevator music format (without vocals) played during the 45 minutes they were set to perform. Hysterical.
The third time was at the Pain in the Grass Festival in 2008 in Washington (State). Again, guy comes out blazing. He blows out his voice halfway through and even apologies to the crowd for it, and can't really sing the rest of the way (although he tried).
So I gotta say, I am very UNIMPRESSED with Brent and Shinedown as a live act. Musically, the band is fine. They dress like a bunch of emo guys trying to play hard rock, but image issues aside, they are solid. But vocally, Brent Smith needs SERIOUS vocal coaching. He has a good voice. He just needs to know how to better use it, protect it and train it.