Back then fbsd had something called accept filters, which basically made the accept call only return when a http request was received in the network buffers.
Systems running fbsd loaded up different than Linux, kept being responsive. On same hardware, could do 3-5x more rps with lower load iirc.
As my applications at the time became more cpu bound, I switched to Debian around 4.11.
I've recently been using 10.x, coming back to fbsd from 10 years of Debian. I love what you've done while I was gone. Especially binary packages and easy upgrades, but especially jails and zfs.