That is true to a point. A good friend of mine is an accountant and has been doing taxes professionally for years. When you pay somebody like that you get a few things. One you get access to a professional grade piece of tax software. Which doesn't matter that much unless you have a more complex return, have prior years taxes that need to be done or some problem with the IRS that needs to be sorted out. The second thing you get is access to somebody, assuming you are using an accountant or an enrolled agent, who studies the tax code professionally. They simply have more time to learn the ins and outs than most people to because it is their job. If your an preparer is an enrolled agent you can usually get them to help you deal with the IRS should you get audited as well. Though they will likely charge you for this.
Still if you have a reasonably simple return Turbo Tax, or any of the other major brand tax software, should be fine. I personally won't be using their online versions though I do use Turbo Tax for my own taxes. On the other hand major part of my friend's business involves people who use Turbo Tax without a full understanding of their tax situation. Where something happens that isn't a simple matter and they try to do it themselves and get into trouble. The biggest problem there is you typically don't know you are in trouble for a couple of years. By the time you do know you are facing a tax bill, fines and subsequent year returns that are also messed up. At that point you are really going to need somebody to deal with it. So the trick to doing it yourself is being prepared to have a realistic assessment of your own knowledge level and be prepared to either study up or hire a professional when you get beyond what you can deal with.