Just wanted to say that I'm working with the "TP-LINK TL-WN881ND" card with the AR9287 chipset and they work perfectly for monitoring; I've not tried injecting any packets.
In fact I'm using three of them in the same computer to sniff on channels 1, 6 ...
In fact I'm using three of them in the same computer to sniff on channels 1, 6 ...