I usually use this software. I am a qualifying widower this year. I entered all of the information into the program that it asked for, yet my return kept getting rejected by the IRS for my late wife's social security number. I switched over to turbotax and entered information and my return was accepted right away. Something is not working right for the qualified widower category. Since I had to pay again for another service to complete my taxes, I wish I could be refunded for this one. Made things more difficult and I wasted my money.
Besides having used this program since it was branded as H&R Block I find that it is very thorough and accurate. I have not needed to use the maximum refund guarantee but trust it would always be there.
Pros: Easy to prepare, Maximizes refund, Easy to import documents, Fast