Well, in The Swarm War we have four factions:
Yun Federation: Democracy, lots of bureaucracy. Couldn't negotiate their way out of a paper bag yet somehow keep order in the Factional Alliance out on the Fringes of Known Space.
Taladir Empire: Demo-Monarchy (similar to the UK, but the monarchy actually has power). Shoots first and asks questions later. The largest Faction in the FA.
Arisa Star Empire: Despot-Monarchy (initially at least). "We come in peace, my what a stabbable back you have." (Again, initially. Gets nicer later on though!

) Medium sized, with reasonable tech.
Karran Imperium: Monarchy. If you do not bother them, they will not bother you without a very good reason. VERY high tech, but small area. Mess with the KI and you get HURT. BIG TIME. And that INCLUDES the GTVA/NTF/Shivans!!

(Though they're not in the franchise, so such comparisons may not be drawn!

)