Both Zillow and Realtor.com pull data from the MLS, and their listings are highly accurate and up to date. Realtor.com has access to a larger number of regional Multiple Listing Services (MLS), but it only shows homes that are listed on the MLS, so it may be missing some for sale by owner (FSBO) listings. Zillow does display FSBO listings, although these are displayed in a separate tab. Learn more about the best home buying sites.