I like unity for a variety of reasons: multi platform publishing, easy workflow, great asset store, native binary support through plugins, etc.
We've done projects using combinations of:
- ms kinect sensor
- asus xtion pro sensor
- oculus rift
- leap motion sensor
- sphero ar balls
- AR middleware such as metaio and vuforia.
- realistic real world terrains from google earth heightmaps
Which take hours to implement rather than weeks/months.