I refuse to buy cable, as I will NOT pay money to watch commercials.
Therefore, I am restricted to "free" TV. Before, we always got a signal, even if a slightly snowy one. We got less channels too.
After the converter, I found that we had a better picture overall in most conditions, but it is always more finicky. We live close to the TV towers (15 miles or so), so the picture is never bad in terms of going in and out, but in some situations, it does just go out (nature of DTV). That said, we have more channels, and the picture is noticeably better.