I am a bit surprised to see someone using the borg set, everyone seems to swear by MACO, but if it works then who am I to judge.
You should check out the United Federation of Planets. While we don't focus on STFs specifically, We have a weekly STF event and an STF group, and there's always people on, so it usually isn't hard to get a group going. I play STFs myself, and haven't had any trouble putting a group together.
We also get together to do other things as well, did a Defera run the other day, and there's plenty more on the event calendar for both PvE and PvE.
I don't really know anything about fleet demographics, be everyone is polite and laid-back; anyone is welcome from the casual to the hardcore. We have a Teamspeak server, though many of us just camp the chat channel shared between the Fed and KDF fleets when not grouping.