Our focus is on developer productivity. That means we try to make things fast, reliable and low overhead.
As far as differentiators, we're pretty fast. We can automatically parallelize your test suite across N VMs. We automatically inspect your source tree, and figure out how to run the tests, without configuration. It's not perfect, but a substantial percentage of customers get a working build on their first try.
We have some pretty cool features in the pipeline that haven't been in generally available products, we hope to blow peoples' minds with them when they're released :-)
Let me know if there's anything else I can answer.