What has your experience been with freelancers from Toptal, 99designs or Dribble?

Dribbble is another league. It is a showcase site for designers. Not a place where you can hire people to do small jobs for you like on 99designs.
People on Dribbble can show that they are open for hiring, but you should contact them as a lose contact where sites like 99designs ar build specific for contacting people.

Thanks. I noticed that they have a paid product that helps put you in touch with designers, do you have any experience with that? Does anyone use it?

I do not. I only know that as a designer you can go pro, and set a 'available' tag beside your profile.

A bit related. Here is an example of a persona that let someone on Fiverr made logo…

You get what you pay for.