Here's how Thumbtack has worked for me.. some guy bids the job at $99 and shows up with a Troy Bilt from Lowes and smells like booze. I bid the job at N/A need more info. Then I show up in a uniform with an obviously larger than homeowner machine, a clean truck and materials with BBB logos, HomeAdvisor best of, screened and approved, PWRA and WCRA logos, etc, and copy of insurance certificate in hand with a leave behind. Win jobs from Thumbtack.
Or I bid jobs on Thumbtack and then I get a sob story about how they have no money. Politely decline the job because if they're that broke they should really redirect that money to groceries and diapers.
Thumbtack in my area is saturated with yahoos without background checks driving trucks like Sanford & Sons. Not always, but often Thumbtack shoppers are price shoppers vs quality shoppers. I'm not a fan despite getting 4 really great customers from Thumbtack and 4 great reviews. I've bid on probably 30 jobs and gotten 4.
HomeAdvisor, for me, in my market, has helped me earn tens of thousands of dollars including multiple commercial jobs. The annual membership is like $400 and the leads are more expensive, $16-25, but the close rate is 80% or better. It's paid itself back many MANY times over.