Are accountants prohibitively expensive in the US? I don't use any tax software myself in the UK - I just pay an accountant $250 once a year and he does it for me (using some software I presume.) It's not really on my radar as things worth trying to automate or use software myself for, let alone building my own software! I'd have to be able to do it in just a few hours to be cost effective.
I found out my parents used one of these places last year, and they charged them about $350 for a SIMPLE tax return. It looked like the goal was to charge about $50 less than the eventual refund, and also push the "get your refund right now!!" scam (i.e. take a high interest loan for the refund amount).
This year, I did their taxes and mine too (separately), using FreeTaxUSA.