I liked the episode. Not my favorite but it moved the story along. Mostly I have questions. What were the 6's all over the motel room for? Were those supposed to be logging camp numbers or demonic omens? Also, seems like the victim of the week had more in common than just virginity such as white female, ages 16 to 24, with long, straight, dark hair. I'm not sure how that is going to work as the Mother of All Evil. Seems like they could have snagged a 30 year old virgin with some battle scars. You can bet the Mother of All Evil is going to look a little worn in. Oh well, we had an elementary school girl as Lilith so I suppose it could work.
I've seen some comments point to Echidna as the possible Mother of All Evil. When I saw that I thought they meant the small aussie hedgehoglike critter. Somebody with art skills needs to draw Sam and Dean facing off with one. One of the things I enjoy most about fandom is how one comment leads to something new to learn about.