I'm going to have to go with Kaew Lom Phet in this one, because Son and Wiew have such amazing chemistry with each other. With Son, yes he his inexperienced, but he is trying and I think that's what counts. Plus, the lakorn always makes me wanting more since it always ends with a cliffhanger. lol ^_^
For Jai Rao, I remember I watched i think three episodes, and Ken and Aff do have chemistry, but Aff's crying is just sometimes really annoying. I mean, I understand she's playing a weak character, but once or twice is enough, woman!
Actually, that lakorn kinda made me like Vicky more and I guess she sort of stands out in that lakorn more than Aff, even though both are really pretty, I guess I like Vicky more in that lakorn. But that's just my opinion
So my vote goes to KLP ^_^