And which users of TP-Link gear are you trying to impress with this statement? See, this is a user forum and if nobody does respond to your description of non-deterministic behavior of your installation, then almost certainly it is not caused by the product itself, but rather by your setup. I guess it's caused by the Windows platform as usual if it comes to intermittent, non-deterministic behavior. Microsoft is a true specialist with decades of experience in this area.
I have been reading your post and trying to figure what is going on. First if your computer has an internal wifi adapter I would disable it under hardware device manager before adding an USB adapter. I have seen many cases where if both adapters are installed windows will have conflicts on which one to use to connect to the router. I would also go here http://www.tp-link.com/us/download/A...UH.html#Driver and do an update on the T9UH after windows 10 does an update. I dislike windows 10 and I refuse to update from windows 7 until microsoft works all the quirks out. As for TP Link products I do not have many issues with their products. Sometimes the problem was a configuration that I made a mistake on.