Many years of practical application gives us to suspect that tweed, as worn by generations of Scottish stalkers, works well on the moor.
If you are looking to buy something and will be stalking alone, i.e. not in a formal setting, then a lot of the military surplus stuff can't be beaten on price and utility. I've been trying it recently and buying off ebay for not a lot of cash.
In the end suitability for the work in terms of comfort, pockets, ventilation, waterproofness and so on is probably more important than the camo pattern as if you are doing hill stalking right the deer don't see you until they are lying on their backs dead.