Masahiro NAKASHIMA

The theme can be changed and displayed to only logged in users.
The visitors of the website see your old theme while you are testing the new one.
Only the administrator of the WordPress site sees the new theme that can now be tested safely.
You can also use this plugin instead of “Theme Test Drive” plugin.

WP Theme Test

I have xdebug installed. There are two big Notices.

Threw two big PHP notices

The theme can be changed and displayed to only logged in users.

shelkie

Manage multiple blogs with a single standard WordPress installation. Each may have its own theme and domain while sharing users and administration.
Handy for situations where multiple blogs or domains are required, but WordPress MU seems like overkill. MiniMU adds this functionality without added complexity or administration headaches.
By associating a WordPress category with each of your domains, you’re able to control where your posts and pages appear. Have some posts and pages show up on a single domain, and others be visible on all domains. Simply assign the appropriate categories to your posts and pages to control where they appear.
You are able to select a different theme for each MiniMU domain if so desired. Additionally, you’re able to change the Blog title and Tagline for each. Often, it’s desirable to include other bits of content that vary by domain. MiniMU allows you to create custom “variables”, and assign unique content for each domain. These bits of custom content may be plain text or HTML.

MiniMU

Manage multiple blogs with a single standard WordPress installation. Each may have its own theme and domain while sharing users and administration.

WP Theme Test vs MiniMU