Also, I was having some trouble getting my URLs to show up clean and the support team worked with me for two days and fixed the issues. Not to mention their response time was less than 24 hours. Well worth the money.
I would suggest paying for the pro, it's cheap and very worth it. You can insert the form into articles (something that is a hassle with other extensions) and you have the option for Captcha. I had an extension before that gave us heaps of spam.
This is easy to use, and the support team is excellent. Don't waste your time with another extension, this one is worth the money. I promise the others will give you a splitting headache.