My experience with Thumbtack was as a business owner.
A couple years ago, when we started working with them, they would send acceptable leads with good conversion rates.
Over the past 8 to 12 months, things have been changing, negatively.
We now receive what they call "qualified leads" who whin't read messages, answer calls or even have a mailbox set to leave a message)
Despite these qualify leads, I'm still being charged. Thumbtack's policy towards professionals makes sense whatsoever.
They used to have an acceptable customer service operation where you were able to talk to a real person who would at least try to get a solution or explain to you why they couldn't accept a refund request.
Now, it is impossible to talk to a person on the phone and can make you wait for hours on hold, and nobody would answer or get back to you.
The way they assign prices to the leads lack of any reasonable logic, as there is no possible way to know how much each one would cost or the chances of someone acquiring a service or how much they have to pay for it.