As far as basic functionality I have no complaints. Ive used TurboTax for three or so years consecutively and have consistently felt it does well at its intended purpose.
My only complaint is the recent interface update. The complete lack of buttons (i.e. "Next", "Continue", etc) in favor of screen-based "swipe to continue" is flat out terrible. The swipes dont work at least half the time, and one must scroll to the bottom of each screen prior to swiping. This makes going back and checking your work slow and painful.
Sylverius about TurboTax: File Your Tax Return, v2.7