I do home searches everyday as an investor. Realtor.com gets it's updates from the MLS; as I understand it, so do other Websites. The problem with realtor.com is, it's drop down menus do not function well, you have to re-enter data when you change a location even though it might be the next town over. And, sometimes the drop downs do not work at all and you can't enter any price selections. The tax data does not necessarily match the tax information from the county's records. The map function is probably tied to googlemaps, however I looked at 10 houses today with difficulty, switching between Trulia and realtor.com because either selecting the price of the home wouldn't work, the actual information on the home would not open at all, or the map location was completely off by several streets. Very frustrating. If you are doing a one time search in one town, it's okay. I'd suggest using Trulia or Redfin which are not perfect, no site is, but they are more consistent and reliable in my opinion than realtor.com.