Actually gamefuel prioritizes traffic via IP address only, which is also QoS, but WISH is a closer match. WISH prioritizes traffic via what type of traffic is being passed (Video, voice, Best Effort, etc). For me, I make sure my video traffic has the highest priority since I want to stream video from my NAS to my 360.
Definition of QoS:
QoS (Quality of Service) refers to a broad collection of networking technologies and techniques. The goal of QoS is to provide guarantees on the ability of a network to deliver predictable results.
EDIT: gamefuel prioritizes certain applications, whereas WISH priortizes traffic on different applications automatically.