For what you’re looking for, this would be my first choice too. And, in fact, my only choice.
You mention that the site is a subscription service. Although the aforementioned Pagesafe stack is the easiest means of protecting a page - it doesn’t (to the best of my knowledge) allow for subscription services. Sitelok does - and handles it with unbelievable ease. Users are able to register on-line and you have the option of automatically granting access - or approving (or denying) access after reviewing. User IDs and passwords are automatically generated - and the user has the ability to recover or change the password down the road.
I have installed SItelok into quite a few sites - and have found it to be exceedingly easy to do. Even better - my clients LOVE IT.
Lastly - although the manual can be quite daunting - the owner of Sitelok has a very small manual designed specifically for installing it into Rapidweaver sites. Use this manual, instead of the huge one, and you should be up and running in no time. If you get stuck, reach out to Adrian - I’ve found him to be very, very receptive to working with me - and have heard similar accounts from lots of other Rw developers (his Sitelok site is built with Rw, too).
Questions? Let me know. I’m happy to help.