I do renderings both by hand and by using the computer and I have found that there is a time for both. Although sometimes it is quicker to do a computer rendering, often that unintentionally indicates to the client that it is a more final design. If you are still in the preliminary stages of a project, a hand rendering might be prefered. I also believe that although you can show detail with both types of graphics, you have to be careful with how much of a solid space you have in the plan view. For instance, if you have a large area of forest or meadow that is relatively monolithic, other than texture and shadows, or a large building footprint a hand-rendering might be more interesting, as you can provide a more variation and make the area seem not as dominating.
