Billie looked great. I like seeing her achieve success with her innovation (the security system). You can sort of tell that all this progress is probably due to not having the burden to deal with her very self-absorbed daughter. I mean, it's not her choice that Chelsea doesn't talk to her anymore, but I think that it's good for Billie. She needs a break from all of Chelsea's drama. And it seems to be doing her good.
As for the Stephanie & Chelsea dynamics, it's not working at all. Especially, since the writers have switched their personalities. Stephanie's turned into Chelsea, and Chelsea's turned into Stephanie/Abby. I rolled my eyes watching Stephanie talk in such a raunchy way. But I also rolled my eyes the way Chelsea acts like she has always been a good girl and a saint.
Despite her claims, Chelsea never was being pressured into sex by Nick. She's the one who was trying to seduce Nick for weeks, and Nick kept putting it off. And she has always had no real qualms about having sex with people even if she didn't have deep feelings for them (i.e. Max, Patrick, etc.). She tried numerous times to get them into bed, but just due to pure circumstance, her plans always fell apart. So, this "I was saving myself for that special someone" is total crap. I just don't like the way writers totally rewrite everything just to drive a storyline or a scene.
I feel sorry for Nick, though. They need to end his relationship with Chelsea for his sake. Their relationship started with real promise, but Chelsea's just too wishy-washy and immature, and Nick has turned into her doormat. And now it's turned into a train-wreck. Nick needs a real woman - not some self-centered girl.