Overall, it was nice to see another MOTW type episode after the heavy stuff of the past two episodes. Having said that, though, it didn't give me as much satisfaction as a typical MOTW episode usually would, mainly because of the Cassifer stuff. I think the inclusion of that meant they didn't have enough time to devote to the MOTW part and it came off as a bit anti-climactic to me...as if it was just resolved too quickly and easily.
But there were some things that I liked and I'll get to those.
First, to the shallow end... Sam in one layer! Would have liked to see more, of course, but it was there. And his hair was very on point in this episode...I'll enjoy that while it lasts. :P
Poor Sam, not being able to sleep and Luci's crap running through his head. Dean is concerned and tells him about a job, wanting him to get his mind off it. Hmm, maybe Dean needs this too, in order to get Amara off his mind.
Cassifer...Hmmmmm. Those facial expressions made me cringe. How did that angel guy know it was him? He was able to sense it, I guess? And later when Dean goes back to the bunker, he's there BSing Dean and trying to act like actual Cas. Meh, Dean admits to him the hold Amara has on him and wants him to keep it close to the vest. Ugh, back to the secret-keeping. *sighs*
The banshee stuff was kinda cool. I was wondering for quite some time if the show was ever going to include them. The deaf girl (Aileen? Eileen? Sam said it one way and Mildred said it another, I'm not sure who's right, lol) was a real red herring there, especially when Mildred told Sam there was no Marlene that she knew of working there, as well as the focus on her as she read their lips about the next feeding time. It would've been sucky if they made her the baddie, so I'm glad they didn't. Interesting that she was the baby whose parents were killed in the prologue. She's out for revenge obviously and Sam tells her it's not all it's cracked up to be. And is it me or was she flirting with him a little? Hee.
Speaking of flirting, oh my, Mildred was quite interested in Dean, almost like that old widow was with Sam back in season 3, lol. Dee Wallace did a great job, although seeing her and her part in this made me feel a bit old myself remembering her as the mom from ET. Another red herring, thinking the banshee was going to go after her since she has atrial fibrillation (my grandma had that actually) but instead it goes after Dean. His weakness is the one he has for Amara, obviously. But don't worry, Mildred saves him and Ai/Eileen stabs the banshee. Just like that. Ho hum. I mean I'm glad no one was killed, but it seemed to be wrapped up a little too neatly for me. Maybe I'm just too picky.
Ah, end scene with our boys in the bunker. Very nice to see. Sam admits to Dean that he was right, it was good to be back on the job. And he tells Dean about Lucifer taking him down memory lane, AND he says he feels bad for not having looked for Dean when he was in Purgatory! Oh, Saaaaaam. :( Dean says he forgives him and that's in the past. Sam seems to feel better but then he asks Dean about why the banshee went after him. Dean is evasive. Ugh, I don't like this. He tells Cassifer but is keeping it from Sam. And I wonder how long it will take Sam to find out about how he can't resist the hold Amara has on him, and what will happen after that.
We get another quick shot of Sam in 1 layer (and is that another old photo of him & Dean in that box? *g*) hitting the sack and seeming to sleep better, but now Dean can't sleep. I guess he is thinking about the Amara crap, though maybe it's wishful thinking but maybe also about keeping this secret from Sam? Who knows with these writers, though.
These are just my preliminary thoughts on first viewing. Maybe my opinion will change during a rewatch but right now it's kind of a mixed bag.
EDITED TO ADD: I rewatched it again today and I found myself liking it a lot more. I really enjoyed the brother moments and I'm glad that they're moving past the whole thing about Sam not looking for Dean in S8. Mildred and Eileen were cool characters - both actresses did great jobs. I also loved Sam's keepsake box with the old pics and the fake Samulet. :)