This is an unsolicited recommendation for X1 Search. http://www.x1.com
This great search tool for the desktop, social media, network shares, and SharePoint and O365 is blazing fast and uses the native SharePoint search. This week alone X1 has already saved me hours by finding lost emails and documents that Windows 8.1 search did not locate. And the screen preview is fantastically helpful.
They have a 14 day trial.