GSA (Google Search Appliance) requires custom integration and is suited only for really really big enterprises. Another similar solution that focuses on enterprises is http://coveo.com

Other competitors: what we see is a plethora of products that focuses on similar problem, but approaching it through consumer sector: https://www.diffeo.com/, https://www.docuvo.com, etc.

We currently aim to serve growing companies with 30–100 employees that are quick to adopt different SaaS tools and are starting to have problems navigating all these systems.