I had to write this because I'm reading reviews from people saying that Usertesting is biased against them because they don't make a certain salary, are unemployed, etc. This isn't bias- it's how Usertesting works in conjuction with companies who need their product tested. If they want it tested by people who speak Swedish (and they will pay quite a bit to get your feedback videos), they should get what they want. It's pretty common for companies to want feedback from certain demographics.
I have been a tester with Usertesting for about four years, and have made between $500-$1500 per year doing it. I have it open only certain times of the day, and have only gotten 1 4-star rating and countless 5-star ratings. It's all about being clear in your speech, continuing to speak honestly, and putting in a little extra effort when they ask questions. Remember, companies who hire UserTesting are PAYING for the privilege of your feedback. Usertesting is just a platform (middle man) for this, and they pay their testers very well. I have received excellent customer service from UserTesting in the three or so times I have reached out, and I find their tools very easy to use. Excellent company!