The S805 is over twice as fast as the A20 on the M1+. I did some tests (also with thermal measurements) when I reviewed another SoC a few weeks ago: http://forum.armbian.com/index.php/topic/311-quick-review-of-lemakers-guitar/
And you will find also results to compare with at mikronauts.com (use the results of Banana Pi or Pro since all A20 based devices perform identical). Regarding an AP capable USB stick we had discussions at armbian.com recently if I remember correctly (but I might be wrong since Wi-Fi available on SBCs is of no interest for our use cases)