Usablenet is leading in Top 100K Sites and Top 1M Sites.
Usablenet has better usage coverage in more websites categories. Including Shopping, Business & Industry, Clothing, Home & Garden and 26 other categories.
Vertster is leading in Computer & Electronics, Computer Hardware, Computer Security, Jobs & Employment and 5 other categories.
Usablenet is leading in most countries, including United States, United Kingdom, Spain, Russia and 6 other countries.
Vertster is leading in Brazil.