What are the differences and benefits to using a Pardot form compared to using a Pardot form handler that works with your own or third party form? Check out the comparison below:

FeaturePardot FormForm Handler
Data De-Duplication in Pardot√√
Data De-Duplication in CRM√
E-Mail Address Validation√√
Progressive Profiling√
Invisible Bot Protection√
Integrate with Third Party System√√
Maintain Current Lead Flow√
Integrate with CRM Web to Lead Forms√√
Support Custom Front End Editing√
Provide Form View/Error Data√
Provide Field Level Change Auditing√√
Can be Displayed in Pardot Landing Page√
Automation Rules Based on Form Views√
Automation Rules Based on Form Completions√√
Send Pardot Email Autoresponder√√
Redirect to Success URL√√
Display Thank You Content After Form Submission√

For more on the benefits of using a Pardot form, see Why should I use Pardot to manage my forms?.  For more information on forms in general, see Forms Questions.