I have and use both the GNX-2 and a POD pro.

If you are after an amp modeling unit, the pod is cool however although it has effects on it, it is not really designed as an effects unit.

The GNX-1 or 2 or 3 however are brilliant for effects but not so hot on the amp modeling.

I have a friend who go one of the RPs and he was also very happy with it.

Best of luck