InspireBooks comes with a classy user interface for the forms created with Gravity Forms plugin. Whether it is normal fields like textbox and dropdown or advanced fields like captcha or date/time field, InspireBook covers them all.
Ninja forms is not yet another contact form plugin, but it is making a mark among all the contact form plugins and is being widely used lately. InspireBook includes an awesome interface for the forms created with this particular plugin.
Contact Form 7
Similar to gravity forms, contact form 7 support is also full integrated with InspireBook. This plugin is widely used and therefore we have taken into consideration even the tiniest of the UI details to make the user experience awesome.
Automattic’s Jetpack has an inbuilt form builder module and similar to other form plugins, InspireBook provides full support for the Jetpack forms too.
So overall you do not have to worry about which contact form plugin to go for. Pick your own choice as InspireBook supports them all.