There are a good number of pathfinding solutions coming out for Unity, which is wonderful. Here is another...
CAINav is a navigation system for use with .NET and Unity Pro on Windows. It includes navigation mesh generation, pathfinding, and local steering features.
The code is available under a liberal open source license, but CAINav is restricted to use with Unity Pro because it is based directly on the Recast Navigation code base. So it operates as a Unity plug-in. CAINav provides direct access to almost all of Recast Navigation's features and includes various Unity extensions to make use with Unity easier.
CAINav is generally meant for use by advanced users. (I.e. A team that includes an AI developer.) Navigation mesh generation is designer friendly. But pathfinding requires coding.
The download site includes a sample pack that demonstrates various features.
All major functionality is well tested, but CAINav will stay in alpha until its API stabilizes.