Hi,
After upgrading from 1.05 to 1.21 I noticed various problems similar to those being posted recently (VoIP failures, DNS resolutions, P2P slowdown) and I stumbled across something that has solved all those problems. I am not saying this will help everyone but here goes my experience:
I noticed in the QoS engine that traffic management was on with automatic uplink measurement, but to my surprise the uplink measurement showed 111 instead of 768. At first I thought I was being traffic shaped by my ISP, but then I notice that the connection type was set to auto. I am on cable, so I changed this to "Cable or broadband network" and viola, on reboot my uplink was correctly showing as 768.
My P2P downloads are now back at normal rate, VoIP etc all all working again, as is streaming.
My theory is that the autodetect isn't working and a lot a peope are experiencing these problems as a result of the very blunt instrument of incorrect WLAN traffic shaping enforced by the router.
If you are in any doubt then I suggest you go to advanced->QoS engine and check what the router thinks your uplink is. I wouldn't be surprised if some of the people having current issues see a very low reading and have a router that is throttling all their backchannels.
Hope this is helpful for someone!