Updated: May 9, 2020
Hmm, yes, it looks like for most users the e505 is basically the same as the famous e500 but it is 75USD less expensive. In fact it has stronger access points because it is Wave 2! Ahh, but here is the differences.
It is smaller and weighs less, easier to hide outside!
It can carry more concurrent users, it is Wave 2!
It does NOT have extra outgoing ports for another access point or security camera. The e500, e501, e502, and the e700 all have outgoing ports to carry security cameras and access points.
So, this is the access point for you, if you need a spherical pattern, outside with great thermal and electrical surge protection but DO NOT need an external port for additional access points or security cameras.