Jim,
Please have my honest congratulations on your Mercedes. It is amazing the result you have got by brush painting totally and it proves the importance of one good brush discipline to paint models convincingly, plus I admire modellers who does not stop enjoying the hobby plenty without traumas, which is really important to me.
Your model has many things I would have painted in a different way, but I appreciate your model anyway because 90% of my paintwork is always based on brush techniques only, so your work is very valuable to me for that reason, because brush painting is very effective to express your intentions and style and that is something hard to master apart of painting technique itself.
Well, I cannot imagine what will happen the day you use one airbrush on your works....
Good work
Lu
PS: Three advices:
1) The only thing I believe your model lacks is dust, something basically mandatory for one desert vehicle.
2) Tires are not bad, but I think you can get soemthing much better if you retouch them a little.
3) Next time if you want to try a different look, paint canvas top at contrary exactly. Paint base color with one light shade and dry brush with a darker one.