Cambridge

The website is straightforward and it's easy to get started. Users are not confused with a lot of information.
You ca read the FAQ and tutorial before getting started, or whenever you need to.
Minimalistic but modern page design. Intuitive and easy to navigate.
Good tutorial for first-time users: includes videos, pdf brochure and on-page FAQ.
Clear instructions. You can always access help features, even during the test.
The interface language can be changed to 4 other languages.
Tests open in a pop-up page, which doesn’t scale well on all monitors sizes. You may have to maximise the page manually.