i've been fiddling with TFO lately, and my BFF Randall found this excellent article on the topic. Well worth a read! Doing some tests, for small requests / responses, you can make resonse times quite noircably faster!
Note: On my modern linux kernel, the command to get the TFO metrics out of netstat is not correct. It should be
$ grep "^TcpExt:" /proc/net/netstat | cut -d " " -f 91-96 | column -t