You have pretty solid control over settings in Lagoa, especially relating to materials - index of refraction, multi-layer materials, etc, are well implemented and exposed to the user. The camera works like a real world camera, so you have that level of control over it (DOF, blades, blade rotation, zoom, etc).
The environment is controlled via dome lights, as well as a physical sun and sky option. We do support image based lighting lighting (applied to the dome light). Yes it is an unbiased system - more information can be found on our FAQ page;
http://support.lagoa.com/faq/. We are a path-tracing engine.
We use CPU based rendering - the machines are owned by a separate company that is a major player in the cloud hardware space.