Sites like Trulia and Zillow will definitely get you more leads than a personal website (in my opinion), just because the name recognition and they rank on page 1 for almost every keyword and address a consumer may type in. Plus, they are know for things like the blogs and Q&A so you also get organic leads if you don't pay for advertising.
Depending on your firm, your company site may be more productive than your personal site. I think it just depends on the route each consumer takes and how much weight the brand of your company carries (boutique firm vs powerhouse).
I do think having a personal website is important either way. People may contact you via other sites, but that doesn't necessarily mean they didn't visit your personal site to vet you.... more