---Which is a better deal: The 1200u/1240u for $150, or the 610u/636u for $50?
What do you plan to do with it? This is a case where if you don't know why you need the higher end, you don't need it. As a pure deal, the lower-end is better. If you don't really know what you're going to do with it, or just plan to use it occasionally to scan some photos to email or put on a Web page, stick with the lower end.