Ceros is leading in Top 10K Sites, Top 100K Sites and Top 1M Sites.
Ceros has better usage coverage in more websites categories. Including Business & Industry, Arts & Entertainment, Shopping, Finance and 62 other categories.
ReadZ hasn't got a lead over Ceros in any websites category.
Ceros is leading in most countries, including United States, United Kingdom, South Africa, Spain and 33 other countries.
ReadZ is leading in Netherlands and Bahrain.