Again, the best way to make sure you see ALL currently available properties each day is to have a Realtor set up an automated search agent for you.
Yes, Realtor.com is a good source. However, I've seen times when it takes a while to update. Sometimes as much as a week. I've received feedback that homes that show available on Realtor.com have already sold. This could have been an isolated glitch and they've corrected, but I'm not sure.
In what market are you looking?
If you'd like to see a list of the hottest new listings or access free reports on the most relevant real estate information in Southern California, such as what you should know before you buy a home, I strongly suggest you check out http://SoCalHomesNow.com
Good luck with your search.
Many agents will steer you to their individual websites to do searches; however, depending on which MLS systems they belong and the area you are interested in, you may or may not have a comprehensive search capability.
The best way to make sure you see ALL currently available properties each day is to have a Realtor set up a (no obligation) automated search agent that works 24/7 for you - it's that simple. Of course, the search will be more meaningful if your individual custom search criteria are known, so please share that with the Realtor you decide to work with so they find exactly what you need.