I just registered to write this review. I am developing for 20 years, installing and using thousands of plugins, but I never saw a scam job like this.
I have no doubt the positive reviews are their team members.
What this plugin does is, let you set up everything, prepare users, create templates and mail, work on the plugin for hours and when you reach to send mail page and click send button, it will ask for login details.
Then you try to register and find out they do not only need classical email passwords. You have to fill a big form from your occupation, company, personal details, telephone number and after register you need to do some confirmations.
In my WordPress plugin usage history, this is the real scam plugin I ever saw.