Mirte

If, for example, your clients want to be able to “turn off” their website for a while, so they can work on new 
content or features of their website, but you don’t want them rummaging through the WordPress Settings pages to do so, this plugin might be something for you.
This plugin creates a very simple little widget for your WP Dashboard, from which the website can turned to / out of maintenance mode.
Activating maintenance mode will display a maintenance mode page with explanatory text for your visitors. Logged in users will be able to view the website as they normally would.
The plugin will automatically create a <code>maintenance.php</code> file and add it to your <code>/wp-content/</code> directory. Customize this page to change the appearance and text of the maintenance mode page.
Known bugs 
* Right now, this plugin will not work on certain servers (like Antagonist.nl) because of a permissions issue.

Dashboard Maintenance Mode

Adds a nifty widget to your dashboard from which you can put your website in maintenance mode.

Chop Chop

OVERVIEW
Coming Soon Chop Chop allows you to create an elegant coming soon page quickly and effortlessly.
<blockquote>
A good coming soon page is profitable for both start-ups and bigger companies to test their value hypotheses. — Matt Tarczynski from <a href="http://woodpecker.co" rel="nofollow ugc">Woodpecker.co</a>
</blockquote>
The plugin comes with a beautiful professional default template which you can fully customize to your needs with our amazing visual editor. It’s simple and flexible and works with any WordPress theme.
Make your site neat and stylish while it’s under construction – work on your webpage when your visitors see an alluring landing page. Collect your visitors’ emails and let them know when your website is launched.
CUSTOMIZATION
Features:
<ul>
<li>Neat design</li>
<li>Custom visual editor</li>
<li>Works with all WordPress themes</li>
<li>Responsive HTML5/CSS3 layout</li>
<li>Quick and easy setup</li>
<li>Custom look and feel without coding</li>
<li>Highly customizable</li>
<li>Google Fonts integration</li>
<li>Social media support (Facebook, Twitter, Vimeo, YouTube, Instagram, Pinterest)</li>
<li>Google Analytics integration</li>
<li>Email notifications</li>
</ul>
<blockquote>
The plugin is exceptionally easy to use, even a novice can easily take advantage of its features. Exactly what a start up requires, recommended to all. — Mohammed from <a href="http://www.moanbox.co.uk/" rel="nofollow ugc">Moanbox</a>
Coming Soon Chop Chop is exceptionally easy to setup and customize so you can have your coming soon page up and running in minutes and get back to building your awesome project! — Oli from <a href="http://photonify.com/" rel="nofollow ugc">Photonify</a>
</blockquote>

Coming Soon Chop Chop

An elegant Coming Soon page in just a few clicks.

Dashboard Maintenance Mode vs Coming Soon Chop Chop