I highly recommend The Evil Echelon, contact @Mr Shock, @Lion., or @Angel's Death for more information. Team with them every now and then, fantastic bunch of people, and really great bunch to be chucked into. Large community unto itself.
I'm sure you could also poke Shockwave/Londoner about MU, the large bastion of PvP veterans who show themselves about on defiant.
Aside from those two titans, there are plenty of little SGs about, if you come across any nice players and fancy joining them 
I'd put my personal playerbase, The Harlequins, into that category, but it depends heavily on what you want from defiant 
Hey thanks for the thumbs up Xem. Much appreciated
And you're welcome on board Jeff.
We're active both Hero and Villain side, and always looking for new players to join our cause
Currently running a regular Vill Team on Mondays, a Vill MA Team every Sunday, plus various SF/Trials on other days (plus the hero activities too)
Shock
Co-Leader of The Echelon
http://www.theechelon.eu
Check out our calendar for weekly events: http://forum.theechelon.eu/index.php?action=calendar
Always trying to keep you in regular teams and doing fun events, if you fancy joining us, then send me a tell to @Mr Shock
Hello all!
I've recently created a Elec/Elec Stalker on Defiant, this is a change in my situation since I usually have my villains on Union.
Well, anyway, is there any SG reccomendations? I'm mainly looking for the common aspects of a moderately large SG; an ideal base; and active players.
So, any reccomendations?