What I have seen in testing the product:
The wireless key captures 1/3 - 1/2 networks and more (of my integrated wireless card) in Ile de France in moderately dense zone.
The little supplied Windows software allows to separate the different signals. This means that if there are multiple freewifi or sfrwifi hotspot nearby, you can see each separately.
The product is compact and for me the usb base is not an overwhelming interest.
I have not tried to 8dbi antenna but only one provided by default.
However, in a sparsely populated area outside the Ile de France, I normally captures an associative hotspot with a very low signal, integrated with my wifi card in some places in the house.
I could test the key wifi tp-link, this one does not improve at all signal reception, which is damaging since I acquired the product in part for this function.