Replacing reCaptcha with SweetCaptcha

Has anyone replaced the reCaptcha field with SweetCaptcha please? SweetCaptcha is a graphical drag and drop captcha plugin. I haven’t looked at the code behind each to see if it’s possible as I thought it’ll be easier to see if anyone has experience of replacing the default captcha option with another first.

Thanks in advance

http://wordpress.org/extend/plugins/easy-contact-forms/