I've checked out Swiftype, and I have to say that it is awesome. It's basically the "Stripe" of site search, in that it fixes a system that was just broken.

Hosted site search as a market has had basically zero innovation since Google launched its site search product. That was like 6 years ago.

If you've ever tried Google site search, you know how much it sucks. It's basically just a thin wrapper around a site:yourdomain.com Google search. It gives you zero control over the index (it uses the public Google index), and it's completely inappropriate for any large-scale site.

Swiftype is a perfect fit for sites that want a high-quality, customized site-search that feels like it was built from scratch. Even if you're already using Solr on your site, Swiftype can be great for creating a lightweight search engine, like for your help/documentation section.