The reason I stopped using Contact Form 7 was because the built-in contact form in CP was hijacking the Contact Form 7 reply-to settings.
Someone could submit a message using Contact Form 7 and it would go to me (the CP site owner), and when I would push the 'reply' button, the address it would try sending to would be <My Site's Name><my-site's-default-email-address>. It would not have the original sender's address in that field.
Perhaps this eventually got fixed, but I stopped using Contact Form 7 in lieu of the Dagon Design one because it worked.