Redfin is pretty good but is in only select cities. IMO Trulia's interface is superior to Zillow's. One small example, on Trulia you can wrap around when cycling through pix. On Zillow you have to go backwards through all pix to get back to the first one. Trulia is more fine tuned like that. On mobile, the gap between Trulia and Zillow is even wider in Trulia's favor.

Zillow shows lot lines, which is nice. Zillow has better price history. I use Trulia for finding a house initially, and then Redfin or Zillow to get deeper info. Redfin has the deepest data.

which areas are you hunting? i wrote a aggregator for some cities at http://twikstik.com, and can add cities for you.