I just came acorss your plugin page and it sounds interesting but am having trouble understanding what exactly it does.
I am currently setting up a classifieds listing website that requires membership for which I am using PMPRO. This plugin sets the member levels, controls registration and monitors expiration dates,etc and has a payment gateway. I use WP User Frontend to create the listing forms which then list as posts.
The reason I am looking elsewhere is there are certain factors that Gravity Forms makes desirable, such as adding a booking form to each post. This is when I came across your website.
I am wondering how Dovetail would tie in with Gravity Forms (with User Registration and post generation functions) to monitor memberships - I am assuming this is what Dovetail does? Can Dovetail restrict the number of posts a user can make?