Even when working in other engines I often use UDK to test ideas, as you can see what's coming out of any node at any point in the pipeline. Writing raw HLSL using text based code is NOTHING like using the material editor even if the end result is a HLSL shader either way.
I agree. But.. Only if you know how to make shaders. I for example have no idea. My usage of Material Editor was dumped down to using multiply and lerp nodes. And on other hand if you know how really make shader you can write in HLSL anyway.