You may choose either one, based on the level of detail you wish to enter.
If the real estate is more of a passive investment, where it is enough to enter net value and rate of return (or dollar amount of return), then Cash & Investments would be fine.
Use the Real Estate screen if you wish to enter the investment in more detail.
Specifically, use Real Estate if…
- You wish to enter expenses at the level of detail of entering gross income, expenses, depreciation, etc.; or
 - The real estate will be sold; or
 - There is a mortgage, and you wish to include the effects of mortgage amortization in your projections; or
 - The real estate is partially residential; or
 - Income will appreciate at a different rate than expenses, and you wish to reflect that; or
 - Depreciation is allocated in a different percentage than ownership