(still probably ~200-250 ms I'd guess)
C:\Users\phil.davis>ping pfsense.org
Pinging pfsense.org [208.123.73.69] with 32 bytes of data:
Reply from 208.123.73.69: bytes=32 time=314ms TTL=43
Reply from 208.123.73.69: bytes=32 time=315ms TTL=43
Reply from 208.123.73.69: bytes=32 time=309ms TTL=45
Reply from 208.123.73.69: bytes=32 time=336ms TTL=45
Ping statistics for 208.123.73.69:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 309ms, Maximum = 336ms, Average = 318ms
The above is at the better end, from the office on a good quality connection. Typically latency to the USA is from 300 to 400ms, but there are times when it gets worse - often in the evening (6-10pm) when there seems to just be bandwidth bottleneck in/out of Nepal - too many people sitting at home eating rice and lentils while watching YouTube :)
I will try some dummynet tweaking delay and packet loss to make it break, since as you say it would be good to know where the limits are.
IMHO this thread is no longer an impact on 2.2.3 - the 5 second delay works fine for me from Nepal as long as I have an ISP that actually provides a reliable connection. So it should work for anyone else on the planet as long as their ISP also gives decent service.
The only exception I can think of is satellite - are there many pfSense installs with the main/only WAN hanging off the end of a satellite link?