To remove the black bars without stretching the picture, you have to resize the game's resolution to a 16:9 ratio. For 720p, you'd do 1280x720 or higher. Then, as long as you're not terrible at video editing/rendering, it should be in HD without letterboxing.
Other than that, it's not absolutely terrible. You need to get used to doing commentary if you're going to do that, though. After that, it could be pretty good.