I was wondering if it would be OK to use this product to lock out an entire site from the public but allow Members Access?
There are other plugins which allows Members Access to specific posts or pages. I've read some of these state that it blocks out an entire site but I haven't seen it yet. Instead, a person would end up on the page with excerpts and a login form. Possibly, the excerpts can be removed but the page still doesn't look right.
With Maintenance Mode, a page appears informing everyone that the site is under maintenance. This message could be changed to something like "Members Only". Then, a custom login slug could be provided to those Members so they can actually view the blog.
My specific concern would be whether or not search engines still index the pages that are within "Maintenance Mode". I wouldn't want any of that to be viewable.