I have tried and played with RobotC 2.0.
It was simple to use as I do have a programming background. But I didn't do much with it since it is not NRC or FLL legal.
Now they have just released a new version, the RobotC 3.0.
Read a V2 -> V3 log on all the improvements (link to botbench pdf)
What I found most interesteding is the new Virtual Robots World (VRW) module look interesting, allowing users to program and simulate without actually needing a physical NXT robot. This could be great for students to practice programming at the comfort of their home.... or for those who needs a little more time at their own pace.
However the new RobotC and Virtual Robots World module does come with either an Annual license or a Perpetual license (free updates till next majar revision).
Download their free trial and give it ago.... I know I will...
[Download page here]