I imagine all professional CPAs use some sort of professional CPA program. The value is in the overall issues that the program doesn't understand. Despite TT's underlying complexity and the fact that thousands of hours of research have gone into the program, it can't tell you the annoying little details of many of the forms - the exceptions, the gotchas.
I quit doing my own taxes several years ago after the IRS came back and asked for $65,000 in back taxes because of some presumed investments that one of my wife's Mutual Funds had screwed up. The accountant took about 15 minutes, found that I had put one number in the wrong place and that the Mutual Fund AND the IRS had put a bunch of numbers in the wrong place - I ended up with a thousand dollar refund.
My taxes are moderately complex - a couple with W2's, 1099's, Schedule C's and some investment income. The entire tax code is batshit insane (like the rest of the country) but I can't do anything about that. I don't pretend I'm a lawyer, an accountant or a pilot. I'll mess with a lot of things, but not my money or my life.