The plugin does perfectly the job it says it does and it's very easy to use. Plus, I completely agree @polanve: it allows you to control your petition being YOU the owner of the data.
Don't use "free" platforms, use YOURS!
Finally, Kreg, the main developer (from DesignKode.com) has done a very good job. The code is clean, he attends the support tickets very well and the plugin is allways up to date. One of my favourite plugins.