We've just recently started looking at Unity for future projects, and in a lot of respects we're quite happy with what we see.
We're now looking at path-finding AI, specifically UnitySteer, but there are no tutorials on the subject.
It's almost as if people are assuming too many steps are obvious in getting UnitySteer to work, and no tutorials on the subject that spell it out step-by-step.
It's a shame, because it looks like it's just what we're after.
I know that the author posts on here sometimes, so any chance of a quick heads-up on UnitySteer.
We're programmers, so we don't need directing to any ridiculous degree, but we're new to Unity so a quick Unity-specific step-by-step for, let's say the Wander behaviour, and we'll work the rest out for ourselves. :)
There are no step-by-step tutorials, but there are multiple examples of how to set up vehicles with basic behaviors. Check out the examples included on the full release, which you can also follow on GitHub here (which requires Unity Pro).
That project contains multiple scenes demonstrating the use of each behavior and, in some cases like the boids, combining them to get a more complex effect. These are meant only to illustrate the behaviors and are meant to be simple, so the example for going to a point doesn't do obstacle avoidance, the obstacle avoidance ones do not flock, and so on.
Finally, you may also want to check out the other questions referencing UnitySteer for the issues that have come up in the past.