Garry’s website is pretty bare-bones, but the plugin itself has been in active development since its introduction.
In my experience, Garry is very responsive to queries and issues.
The UI isn’t the most intuitive, but it is highly logical — and the extension is extremely capable and full-featured. He’s produced a series of video tutorials that cover all aspects of use to help you through the learning curve.
The demo isn’t crippled in any way — just limited to 7-day trial. Best to download it on a week when you have enough time to devote to learning it.