Fast, intelligent, and fully customizable search for your site. Comes with detailed analytics and controls in the Swiftype Dashboard.
This plugin works great for small websites. For large websites with over 10,000 posts, they charge $179 per month. There is no indication of the fee until when you install the plugin. A few weeks later an agent will send you an email telling you to pay up or stop using the plugin. This should have been mentioned during installation.
Another example of freemium software using misleading tactics to ramp up business. Some sort of mention of the fees should have been included on the WordPress.org page.