Thanks for the reports everyone. We have been doing a lot of work on the Wifi drivers (especially Realtek) and a new kernel with updated drivers will be pushed out soon, probably together with an RC2 release. (If you are on the current RC you will get all the changes just by running an update, no need to reinstall)
The adaptors I have personally tested on the not yet released RC2 kernel are:
Tenda W311M - idVendor=148f, idProduct=5370 (working ok in both RC and RC2 using rt2x00)
TP-Link TL-WN823N - idVendor=0bda, idProduct=8178 (random loss of connection, slow performance and complete system hangs in RC, working ok in RC2 using 8192cu)
D-Link DWA-131EU - idVendor=2001, idProduct=330d (not detected at all in RC - working ok in RC2 using 8192cu)
Edimax EW-7811UTC - idVendor=7392, idProduct=a812 (not detected at all in RC - working ok in RC2 using rtl8812au)
Obviously this is only a small selection of devices compared to what is out there but it covers 3 of the most common drivers. (especially the problematic rtl8192cu which we have replaced with 8192cu)
All of these adaptors seem to be performing well (within their individual limitations) - within the same room to a dual band AC base station I was seeing measured iperf throughput on my Pi 2 of up to 156Mbps on the Edimax, 116Mbps on the D-Link and TP-Link and 54Mbps on the Tenda.
When RC2 is released this thread will be closed so as to avoid confusion and another thread for RC2 may be opened if there are any remaining unsupported adaptors.