The first thing that'll grab your attention is the program interface. Sometimes it seems oversimplified, like it's lacking options that might have been interesting. Because of this, though, creating any element is as easy as following the steps and simply clicking 'next.'
You can select the size, shape, and color of the menus and buttons, and insert whichever text and images you'd like. Also, of course, you can choose another image to be shown when the mouse is hovering over the button.
OK Button may be useful for users who have absolutely no knowledge of graphic design, as it's so easy to use that anyone can do it. However, its features are rather subpar when compared with those of most competitors.