Depending on the application, I'll use a Finite State Machine pattern, but if I need something more complex I'll use QM QP/C (which is uses a hierarchical state machine pattern).

So it's good to see others using Quantum Leaps RTOS. It take a little bit to set up the environment and understand some of the bounds, but I really enjoying using their QM Modeling tool[1], I would recommend it. I would mainly use it for the logic and abstract out the code in separate files, so that you are not maintaining code in the GUI tool.

[1] http://www.state-machine.com/products/#QM