Custom Map Makers

Which program is best for creating simple models for map?
Milkshape, Misfit, Blender?

What is important is time required to learn the basics.

You can try gmax, i learned a lot from this great tutorial Its way harder than milkshape, but its completely free, and with more capabilities. Here is md3 exporter

I think you should think of what you want to learn in the end.
I started out hoping to just make models, so i went an easy way.
made a few bad models and faced i needed to learn something better.
I am trying to use blender as it will be usefull when i know how to use it.

I tested milkshape and made a few trees in like 30 min after opening the program for the first time. I guess that sumens it up well.

If you need to make less complicated models you could just make them in radiant and convert them to .ase models as well.