I've used https://usabilityhub.com/ before, it worked really well. Really nice how you can take other peoples tests to get yourself free testers.

Another vote for https://www.usertesting.com here.

https://www.usertesting.com/, you can try a free session here http://peek.usertesting.com

I have had great success with usertesting.com. The turnaround time is very good.

Fullstory is essential for me. I use it to understand how people use the products I work on and to find test participants. It's really great. You can filter by relevant parameters (by feature, by email, by location, etc) and watch videos of people using your product.

If I see something "interesting" happen in a video, I'll send the user an email and follow up with an interview and/or show them a prototype for something new I'm working on.

We use user zoom for quantitative testing. The interface isn't pretty and it's expensive but it has the flexibility for running rigorous studies and asking all the questions you could need. You can also use it for smaller formative usability studies if you need to.

Hey Hillel, Matt from UsabilityHub here :) Thanks so much for the shoutout. Is it cool to reach out to you via email? I’d love to know how you’ve been finding our product and if there’s anything we could be doing better.