Testing other firmwares right now, but I'm not getting anything better than my stats with the original firmware.
Using a network cable, my internet speed was the bottleneck. Pingtest speed test shows how using one speed test app alone can give bad picture, from 14 to 37 Mbit reported between apps, timing was pretty close. As with watching videos, some servers get overloaded, and can't supply enough bandwidth to your connection.
Anyway, for anyone interested,
ethernet downstairs
ookla - speedtest 37.94 down 18.02 up 17ms
ookla - speedtest 2 37.90 down 18.49 up 17ms
pingtest - 14.96 down 9.27 up 50ms
pingtest2 - 14.37 down 4.9 up 49ms
speedchecker - 33.5 down 16.91 up 34ms
speedchecker 2 - 32.45 down 15.2 up 29ms
Samba 1.71MB/sec
For the sake of comparison, my PC on a cable got 35.36Mbps down 17.81 up 17ms with Ookla.
WiFi was the same as old firmware, with results like this:
speedtesk ookla - 28.62 down 18.52 up 17 ping
speedtesk ookla 2 - 30.74 down 18.31 up 21 ping
speedchecker - 29.77 down 25.04 up 42 ping
speedchecker 2 - 30.5 down 13.42 up 48 ping
pingtest - 23.43 down 12.08 up 65 ping
pingtest 2 - 28.24 down 14.31 up 53 ping
samba - 1.15MB/sec