There is a slight change in terms of hardware. V2.1 is better V2 all in all.

Hi, TL-WDN4800 is not compatible with Mac

Hi Yago, Tplink official driver doesn't support monitor mode on Linux. You may search a suitable driver in Github. If you don't know which chipset, tell me the hardware version of the adapter. Or...

Yes they are compatible. The link rate between two different model will be based on the one of lower speed 1300 Mbps.

Hi Peter, Check on both units. Hope this helps. https://www.tp-link.com/en/faq-2027.html

Hi, Yes the difference is that PA9020P is passthrough. It's OK to mix and match both types. They are of the same standard, no difference in performance in theory.