It all depends on what you consider simple.
There is Zaxworks 3d invigorator that alot of people I know use when they need a quick 3d object in AE.
I personally use 3DS Max to create all my 3d and render seperate layers so I can add glows to what I want and so on. that way my neon glows a little and my clients like it.
It just depends on how deep you want to get into a simple 3d sign.
Eddie