It's really hard to contest that, but at the same time I feel like they have greater chemistry than most other characters. You've gotta remember during her capture she technically asked him out (she wanted to go to a restaurant with him later) and then Keima snapped. lol Just a couple chapters ago in the guitar store they were like two peas in a pod before she could even notice it and ran away in "disgust". She couldn't hate him if she wanted to. lol
What I'm trying to say is that she is naturally at ease around him and that's bigger than whether he's a perfect member of society...okay yeah she has bad taste.
But I like her taste, thank god for girls who dont need a 10. LOL