There are two types of domain name values ... reseller value and end user value. Reseller value is always way way way way way lower than end user value and honestly about 90% of the time, you can get a pretty good idea what the reseller value of your domain is from EstiBot. It's pretty dead on most of the time. Sure not 100%, but what automated service is ever really perfect?
Resellers are like day traders in that they buy low, sell high and tend to do it for the sole purpose of reselling the name - like stocks. They have no real vested interest in the company of the stocks they buy, they just want to make a quick buck. :P
An End User is typically a single person or company who has a specific reason for wanting to purchase a domain name such as they want to brand it for marketing purposes and almost always have a vested interest in the related product, service or company.
The end user will pay WAY WAY WAY WAY more than the reseller but there are far fewer end users than resellers and as such, it may take a LONG time and a lot of patience to find the right buyer (or any buyer for that matter).
For example, a domain like MedicalKnowledge.com (just one I grabbed found in this thread) is a great end user domain and might easily fetch $5,000 from the right end user but from a reseller maybe only $500. Same domain, two very different reasons for buying it and as such two very different pricing schemes.
Now onto LEAPFISH ... leapfish has pricing more geared toward the end user however it's not always really accurate. It tends to over price domains based on things that most end users don't care that much about such as the age of a domain. Sure that is important but most end users care about how cool the name sounds, not the aged value of it.
Here is a real example of the correct values of these services. I am selling two domains -- both domains are being offered up for $7700.
ESTIBOT puts All4U.com at $1100 reseller value and $12,000 reseller value for AllForYou.com. Actually it was much lower the other day $3 - 4k or something ... I think soemthing has changed. But anyway ...
The total value according to Estibot is $13,100 RESELLER.
Leapfish puts the value of All4U.com at $557,324.00 and AllForYou.com at $87,248.00. That's a total value of $644,572 END USER.
Big difference huh? Well the reality of the situation is, I tried for months to find a buyer for those domains at $11,000 with no luck so recently lowered the price to $7700 which will be the final sale price. I refuse to go any lower. :P
But the point is ... the value reseller or end user and the reality are never really one in the same. All you can do is use those tools as a building block for helping to come up with a fair and reasonable price.
But if you are in a bind and you just must know if something has a reseller value rather quickly, EstiBot really is pretty dead on most times with reseller values.