The two companies go to great lengths to try to distinguish their programs. Block stresses the backup provided by its nationwide network of professional tax preparers. Buyers of its Premium edition can receive a phone consultation with a Block staffer. The company will also provide the help of an enrolled agent — someone trained specifically to prepare returns and represent taxpayers before the I.R.S. — if a customer is audited.

Intuit, in contrast, emphasizes the ease with which TurboTax dovetails with other sources of financial data. Quicken users, for example, can transfer all of their information into the program with a couple of clicks.

Read the full article and see which is best for you.