I did my own taxes first by hand then using software for years, until I was laid off from being a wage slave and set up a small business plus was collecting income in 2-3 states from 2 jobs. Then I used accountants for several years , both to learn about the complexities of business taxes (the business tax software doesn't do nearly as much hand-holding as the personal, I found) and to handle the multiple state returns, until I moved to a new state and settled down again.
I'm now back to doing my own, just working in one state with the side business, because I can use the ones the accountant did as a guide. I also learned useful things from conversations with the accountants about how to handle the accounting for the business, which I found more confusing than doing the taxes, actually.
I see why people recommend doing it by hand, by the way, having that background let me know to hunt for options in the software which I would otherwise possibly missed, and let me know to ignore certain things as not applicable. The number of confusing or obscure options has easily doubled in the last 10-15 years. I also found that doing by hand doesn't take much longer than using the software, most of it is finding the relevant information in your documents. However, one big advantage of the software is when you find something you missed, a new rule, a new receipt, etc., and change an entry, everything recalculates. I don't think I've ever had a year when I didn't change SOMETHING in doing the return.
The other advantage is that sometimes it raises an option you might not have found on your own, much like a (good) accountant. A risk to doing it yourself with the free paper or pdf instructions is that there are some tax breaks which may be off in their own instruction book, not mentioned anywhere else, that you don't know to go look for.
Finding a good accountant is not trivial, mind you, I recall a yearly Money magazine contest they used to do where they sent a fictitious family tax return to 50 tax accountants each year. The most correct returns they got back I ever saw was 2, one year it was 0. So somewhere between 0% and 4% of accountants are "good", sigh. . . :) On the bright side, if you get audited, which you may have higher than average odds of with $150k of taxes, the accountant normally has to help out. That could be worth something too, given that penalties could be pretty high with such a high tax bill.