I made some comparisons between Ansuel's NSS and hnyman's build:
Ansuel hnyman Ansuel Ansuel
hw flow offloading no soft offloading
iperf3 550 Mbps 910 Mbps 815 Mbps 610 Mbps
(wired)
iperf3 400 Mbps 700 Mbps 450-600 Mbps 480-640 Mbps
(wireless)
bufferbloat B A B C
(wired)
speedtest 77 Mbps 270 Mbps 100 Mbps 270 Mbps
(wireless)
uptime few minutes stable > few minutes > few minutes
Although low CPU utilization during tests involving routing looks promising stability and to lesser extend performance are still an issue.
Not sure whether difference in performance is because of lack of some patches and tweaks or if there is different reason.
Would it make sense to disable software flow offloading?
EDIT: in order to be able to turn on hardware flow offloading software flow offloading has to be checked. Table updated with Ansuel's repo with disabled software flow offloading.