No pics!!!?!?!? I was in the market to steal a giant flat something or other but I guess I will have to find something else.
For either process, no, not really. The additive machines will be limited by their build resolution but that will mostly hurt small features. Considering the size of your part it seems that you may not have too many small features. The milling machine will not be much bothered by feature size either but it will come down to how stable your component can be held in place and what material you use.