Coinhive is proof of work captcha widget, alternative to Google's reCaptcha. This prevents spam at an inconvenience that is comparable to a classic captcha and provides the added benefit of earning money from user's' form submission.
Coinhive Captcha is leading in Top 100K Sites and Top 1M Sites.
Coinhive Captcha has better usage coverage in more websites categories. Including Computers Electronics & Technology, Games, Arts & Entertainment, Gambling and 12 other categories.
Sweet Captcha is leading in Food & Drink, Travel & Tourism and Vehicles.
Coinhive Captcha is leading in most countries, including United States, India, Indonesia, France and 44 other countries.
Sweet Captcha is leading in Germany, Canada, Australia, Albania and 7 other countries.