Usablenet is leading in Top 100K Sites and Top 1M Sites.
Usablenet has better usage coverage in more websites categories. Including Shopping, Business & Industry, Food & Drink, Food & Grocery Retailers and 34 other categories.
Vertster is leading in Computer & Electronics, Computer Hardware, Search Engine, Relationships & Dating and 5 other categories.
Usablenet is leading in most countries, including United States, United Kingdom, Spain, Italy and 11 other countries.
Vertster is leading in Australia.