Usablenet is leading in Top 100K Sites and Top 1M Sites.
Usablenet has better usage coverage in more websites categories. Including Shopping, Business & Industry, Consumer Electronics, Sports and 33 other categories.
Vertster is leading in Computer Hardware, Computer & Electronics, Furniture, Science and 5 other categories.
Usablenet is leading in most countries, including United States, United Kingdom, Spain, France and 10 other countries.
Vertster is leading in Australia and Portugal.