I've been using H&R Block software to prepare our state and federal tax returns for years--can't recall how many. One time I tried the competition and found it so complex, labor intensive, non-intuitive, double work, that I dumped the product and went back to the H&R product for that year. I've never strayed since. On three occasions that I can remember, I took the H&R returns to CPAs for review and to learn that there was nothing to be changed. The expense was between five to ten times what I paid for the H&R program PLUS I had to do just as much work to gather the information for the CPA as I would have done to complete the H&R returns.
Pros: Easy to prepare, Easy to import documents, Fast