As a recent home buyer, I found Zillow information to be at least one week out of date. In most cities, that probably isn't a big deal; however in the San Francisco Bay area I found the site pretty useless because all of the homes I was interested in, I was unable to see because they were usually off the market, pending or very late in the process where I was unable to visit the home.
I ended up using a Sotheby's owned site, with accurate data.
Additionally, their Zillow Estimate information is at least 20% low in SF, even by admission of their own analysis: http://www.zillow.com/zestimate/#acc
The benefit I should mention is that I met a great Realtor through their ads, which he admitted to spending thousands of dollars on per month on.
To be fair... in a lot of SFBA locales, homes are selling for 20% over list anyway. So even sellers (and agents) are having a hard time pricing the demand.
I think that's a quirk of how this type of auction pricing works more than anything. If everything in the area is going for 20% over asking, then posting a listing for what you actually think it's going to go for will make it look 20% more expensive than comparable properties, so you may get less offers. So there's this strange feedback loop that happens in local pricing, magnifying the list vs sold price disparity.
Realtors are often encouraging sellers to list below market rate to encourage bidding wars. When you have to go through several of these before you can get into a house, it causes quite a frenzy in people. This isn't the norm across the country.
In other markets, realtors usually have clients list houses above market value with the expectation the sellers will come down.
my realtor was able to estimate the price better than Zillow, I feel like they need a better machine learning model to accommodate different markets. (Denver, SF and Ohio are very different places)
In my recent long home search period, I didn't trust Zillow's price estimates at all. But i used Zillow religiously because it's UI/UX is just so good, so much better than the competition, I could do a survey of what's out there easier and quicker, and find out more of what I wanted to know about interesting listings.
Zillow "zestimate" seems to be something they're known for, but I don't think it's actually their strength as a product.
I ended up using a Sotheby's owned site, with accurate data.
Additionally, their Zillow Estimate information is at least 20% low in SF, even by admission of their own analysis: http://www.zillow.com/zestimate/#acc
The benefit I should mention is that I met a great Realtor through their ads, which he admitted to spending thousands of dollars on per month on.