Both Mako on my Bounty Hunter and Corso on my Smuggler are lightside oriented. That's fine with me, since I play all my characters lightside.
On my Sorc that leads to problems with my Sorcs first companion Khem. He is a Dark Sider and so it's - a lot every time I've used him in conversations. But that's ok, the feeling is mutual. I dislike the big ugly brute myself.
Playing my Smuggler mostly nowadays. And I'm using Risha exclusively. And even though she doesn't agree with all my decisions. My smuggler and her do share the same sarcastic humor / snide remarks, which grants a lot of + and she also loves credits, which makes it even easier to raise her affection. I'm almost at 5k affection with her. Just with chatting and a few gifts I pick up through my Diplomacy skills.