These are my personal opinions based on my background and training experience.
From their website:
"Hack The Box is an online platform allowing you to test your penetration testing skills and exchange ideas and methodologies with thousands of people in the security field."
My reviews are of the Pro Labs, which are simulated corporate environments. These are red team like environments. They recently changed to a subscription based approach giving you the option to pay monthly or yearly.
And while I will not be reviewing the machines in Hack The Box's active/retired areas, I highly recommend those to anyone interested in red teaming or penetration testing because I have learned some great tricks.
Visit their website at https://www.hackthebox.eu/ to get started today.