MaxiFi is a long-range planning tool that helps you to build life-cycle models (i.e., models that reflect various periods of saving and dissaving; children in the house, children left home; working, retirement, etc.). It is not primarily an asset allocation tool or an investment analyzer that shows historical yield, standard deviation, or any other kind of data you might explore about funds or asset classes. Portfolio analysis is typically free at your brokerage or investment company like Fidelity or Vanguard.
The very powerful and free tools that do statistical analysis, back test analysis, asset correlations, factor analysis, and portfolio optimization are useful in context but in no way capable of doing what MaxiFi can do. MaxiFi is designed to discover safe lifetime spending, saving, and withdrawal amounts that also account for your changing federal and state taxes, your future receipts like Social Security, pensions, as well as your mortgage all in the context of your inflation assumptions. This discovered spending amount can serve as a reliable benchmark against which you can measure the impact of any future financial what-if event: How does spending an annual sum of $36 or $36,000 15 years from now change my spending this year and every year thereafter? How much is this lifetime annual spending changed if I postpone SS until I'm 70? If I assume an average nominal return on my retirement assets of 6% instead of 3.75%, how much would my annual discretionary spending change?