Josh Woodward rates this 3 / 10:
After spending hours filling out tax forms online through hrblock.com, and getting ready to file, I proofread my forms. They said I owed hundreds of dollars in underpayment penalties, but since I had filed the required estimated taxes from the previous year, I didn't owe anything. The reason? They assumed "0" for line 8 of form 2210, and give no way to fill it in. These guys don't have their act together. Skip them unless you have super-simple taxes.