I have not used the Duiker, but the Arrowmaster has been excellent in every regard so far. Good sized pocket, easy to get to, and put away arrows, easy to get out of the way when you need it to. The only changes I would make are:
1. I wish the D rings were metal, like a dull finish anodized aluminum, but that's something I can change.
2. I wish the strap were wider, with a slidable pad, like you get on a duffel bag. I have one from a backpack I may try to retrofit onto it with Molle webbing on it that I can maybe stick a multi-tool or something on...
--Kyo