It depends on the types of clients you have. ProSeries Professional may be a good fit if you have a high volume of returns, do business returns, or have more than one preparer in your office. Professional contains both individual and business forms, and a variety of time-saving features (K-1 data import, a client checklist, etc.) for professionals who require high efficiency. ProSeries Basic may be a good fit if you focus on individual returns. You can compare features here to find the perfect fit for you.