Thanks for your question. I am a local realtor in Manhattan. The only answer I have for you is that different systems are better for different area's depending on where they market and focus their activities. While Trulia may be HUGE in Chicago or Seattle it may be light in places like Manhattan. I have a couple of tips for you;
1.) Try Realtor.com. This site is endorsed by the Association of realtors and is fed directly by local MLS feeds. This means that as far as the National property search engines it will have the most current and complete data.
Best of luck in your home search.