I agree with your concern, and would like to hear similarly. When I started using Turbotax and Taxcut I ran the numbers by hand "just to check." Everything was fine. Obviously, these are no good if you have to do that every time. For that reason, I lean toward the H.R. Block program as they claim they will pay interest and penalties on any increased tax liability resulting from an error in the program. Of course, one has to say immediately: "Yeah, try and collect!"