I have tried others, but there is always an error. As someone who works in one state but lives in another state, only H&R Block has been able to correctly calculate my federal and state taxes every year. I strongly recommend.
Pros: Easy to prepare, Maximizes refund, Easy to import documents, Fast
Straightforward and fairly easy to use. Would benefit from better help. If you buy the state add-on, you have to pay a hefty filing fee in addition to initial cost.
Purckase, install, data entry, updates and on line filing were smooth as goat lips. H R Block allowed me to focus on my taxes and not be distracted with technical difficulties.
I've been a fan of Taxcut for several years, and appreciate the ability to use it offline and for multiple returns and multiple states (with purchase after the first free one). It is in general easy to use and simplifies the tax process.