We're operating at a layer below other analytics products, and we're certainly not as useful out of the box. A good analogy might be:
MailChimp : SendGrid :: Google Analytics : Keen IO
Which is to say, Keen IO is a set of developer API's wrapping hosted infrastructure, whereas other analytics products are end-to-end solutions. We're an agnostic event data backend, and they are each a full product offering with its own focus.
Hopefully that helps explain why we don't think of ourselves as competitors to products like Mixpanel or GA or KISSmetrics -- in fact we plan to build one-click import and export connectors from/to those services and others. We think our position in the ecosystem will actually help them retain customers who would otherwise churn in favor of building in-house.