Q1 - is anyone using QOS successfully, and if so how?
Yes but only in my DIR-855 for VoIP - just set high priority for the telephony adapter.
Q2 - is anyone using WISH successfully, and if so how?
WISH prioritizes wireless connections in your internal network, it slowed down my wireless, so I do not use it. In most cases there is more sense to use QoS on your internet connection as it is the bottle neck.
Q3 - is anyone using QOS&WISH successfully together, and if so how?
No
I have 3 devices connected into the DAP, but there are never more than 1 in use at any time (PS3 or XBOX 360 Elite).
If there is only one active connection at a time, there is no use of using QoS except this device hosts different timecritical services used at the same time (i.e. gaming, video streaming, VoIP).
I can imagine that using QoS in your router and bridge may interfere if not set properly.
Different chopsets may handle QoS rules in different ways that do not work together properly.
At least I did not notice any advantage enabling QoS in the DAP menu. So I leave it off and everything works fine