One good plot thread, and one bad one. Let's take a quick look.
Cons:
The plot thread I didn't care for involved Raj and Penny getting really close and spending all of their time together now that Raj has moved in. Leonard feels left out. After being a third wheel with Howard and Bernadette for a while, he decides to tell Raj and Penny how he feels, but they humorously continue to leave him out of the conversation as they discuss his feelings. This feels like yet another example of some serious issues in Penny and Leonard's marriage being hinted at, but never actually developed. We've already seen this kind of scenario play out in the past, with Raj interfering in Bernadette and Howard's marriage. It feels like a retread. And there's no really good punchline either. Leonard is feeling jealous, he tells them that he's feeling jealous, and everybody just kind of shrugs their shoulders and moves on.