Based on my personal taste, the dev blogs, the uniforms, and what i know about the Romulan story and canon i will chose:
Everyone seems to be choosing the Federation, that's weird to me, the Federation have been against the Romulans since United Earth. The Klingons have a history with the Romulans, good or bad. Besides if you were a Rebel/Smuggler in the Romulan flotilla you would hang out in the bad part town in Qonos in the bars and clubs, not admiring the Galaxy Class on Earth Spacedock. The uniforms look bad TRIBBLE, compared to the federation, you can still get the smuggler outfit anyway from the neutral set and that looks better than the Federation variants. Plus its more logical for the Klingons to help you out anyway since they have also have history of giving arms to small bands of Rebels like the Maquis in DS9 to fight the Cardassians hence the Juggernaut episode of Voyager which was the inspiration that created the Bio Neural warhead for the game.
Klingons seem more open and honest about their feelings toward us anyway and i rather have that then the Federation bottling up their true intentions and Sector 31 breathing down our necks, we already have this new enemy and the Tal Shiar.
More weapons, more guns, orions, perfect for a smuggler Rommie like Han Solo.