This episode was great, even Raj was bearable and Amy, who I started to really like in season 4 was very funny. Her secret language was hilarious as was most of her lines. So was Sheldon, specially his sacrifice.
I always thought Penny sleeping with Raj was kinda funny although not as funny as the outrage of some of the fans. It's a televison show folks... get over it. I thought the aftermath was pretty nicely handled although it was kinda cheap.
I felt this episode captured the feel of season 1 and 2 and I really hoped that continued this season, although after seeing episode 2 that hope was crushed.