Best free (beta) Cyber Testing platform?

I have stumbled across this potential useful Beta testing platform where users can try to complete certain new cyber related tasks - I am not sure since i am still learning and just joined today but what do you think?

Is this a good testing ground to try to implement what has been learnt on the provided course?
Is this a good platform to direct students to try out? A social testing platform?

The link above is as follows:
http://Public.attackdefense.com

Note: You will need to use your Google account inorder to gain access

I am not in any affiliation with these guys - I have only found this and ought to share it since we are all trying to learn and improve our skills.