These are my personal opinions based on my background and training experience.
To quote directly from their site:
Take your Hacking skills to the next level.
I signed up, logged in and went through a few boxes (if my memory serves me correctly). I remembered this site because I recently got several e-mails from them about changes they have made to their site such as a support page, a profile and settings page and forums. I need to revisit this resource!!!
Visit their main page at https://practicalpentestlabs.com/ for more information.