Neither site's valuations are worth more than for entertainment purposes. No one from any auto-valuation companies views the home, sees the condition, improvements or deferred maintenance.
If you looked at 5 different companies valuations, you'd get 5 very different views and none of them may be right.
If you need a more precise idea of a properties value, a local realtor who serves the area would be your best bet. We are in the homes, comparing them, helping update them and of course selling them.