I have BOTH of these adapters. Both appear to be perfectly PnP in Kali-Linux. If I plug in my AWUS036NH the Linux reports the Realtek chip RTL8187 with driver RTL8187 on wlan0. If I plug in my AWUS051NH Linux reports a Ralink 2870/3070 chip with driver RT2800USB and firmware RT2870.bin. From this I gather that both AP's are loading properly with the correct drivers.
Both adapters enter monitor mode. Both adapters acquire handshakes and seem to perform all the other aircrack-ng functions pretty much equally. I suppose I could say that the 051 might attract more access points than the 036 but honestly, moving either of them closer to the window that is closer to the building next door produces a more noticeable improvement!!
Neither of them will work well at loading web pages or downloading files unless the originating signal is a good strong one, so while it may be fun to identify a far distant router, the only practical way to make use of that information is to move closer to the router!
If you have a good strong signal I suppose I could say that speeds are better with the 051, but I don't think I gained a lot by getting the 051 that my existing 036 didn't already do.
