Just spent the day digging through a box of old gear to relegate for network extension duties. These tests were done in bridge mode from about 20 ft from the main router through 2 walls.
Netgear X4S – No surprises here.
Asus RT-N66U – A bit long in the tooth. Pings aren’t consistent.
TEW-680MB – Pings are very consistent as well as connection speed. Great value!