Eugene-Springfield area of Oregon. 3/2 ranch home, attached 2 car garage, built in 1976, 1781 sqft on 2.84 acres (no idea how many tomato plants would fit!) Bought in 2006 (near a market high) for ~350k.
As of April 2018, Redfin (Zillow doesn't seem to know our home exists) claims a current market estimate of ~$430k.
The Chase bank home value estimator gives a range of ~$375k to ~$588k.
I am skeptical of the high skew by both tools - prior to using those tools my own assessment was ~$380k.
At least in our area, it looks to me that these online estimation tools are estimating too high. I've seen homes go up for sale near Zillow's estimates and invariably after several months the sellers drop their asking price to make the sale - this in a market that had an average 1.9 month inventory during 2017.
My Realtor told me tools like Zillow and Trulia are not accurate, because they don't know what the inside condition is like..just a ball park figure.