Okay, here's what I have to say:
I have always hated Cinder. Like, not just in a, you're such a jerk stop killing people and instigating fear and distrust among the masses way, but in a, I want to smack that smug look off your face way too. But now? Seeing how badly Ruby messed her up (and she deserved it, don't get me wrong), and seeing her go from being super confident and smug to demure, quiet, and just generally looking way more pathetic, I kinda feel sorry for her. I saw someone on TV Tropes point out that she was pretty much acting like her boss, Salem, with Mercury, Emerald, Roman, and Neo. Interesting, she may be a deeper character than I once thought.
Speaking of Mercury and Emerald, something tells me that they have got way more in over their heads than they thought they were gonna be. I mean, did you see the way they reacted to the Grimm's... Spawning place? (Or whatever that was.) I'm not calling them switching sides juuuussst yet, but I don't believe it's 100% out of the question.
It'll be interesting to see who the Spring Maiden is too. Wonder if they found the Winter one or not...
Ah yes, here's Team RNJR. Or JNRR. (I like RNJR more personally.) They do a big fight with something, like they've done with all the first episodes of the series, likely to establish a tone, get you excited for more plot, and give you a sense of setting and direction for the current volume. 
Aww, Jaune has Pyrrha's sash. Also, awkward random anime face from Ruby when she laughs at his hoodie is awkward.
Yay, Weiss! I'm ready for some Character Development from her, and everyone else too.
I'm glad that the intro is more upbeat that Volume 3's. In fact, I think this is the most upbeat one we've had so far. 
And that's what I think. It looks like things are gonna be good this volume. I hope the pace is alittle more like Volume 3 (especially the second half) and less like the first 2, because I really, REALLY wanna know what is going on.

 
-Blake! I missed you. Yay, you got rid of the ribbon!
-YANG. I MISSED YOU EVEN MORE. AHHH.
-Taiyang is like greatest father. He tries.
-Yang, I want to hug you so bad. It actually sorta looks like her PTSD is worse than Ruby's (although we never really saw what Rubes was dreaming about in the last episode...)
-Ooooh, water-wyvern Grimm!
-Sweet, Sun is here (also MOAR BlackSun yay)
-I really want those people in the intro to be Blake's parents and for Mr. Belladonna to be super suspicious and scary around Sun and him to be a huge sweetheart to Blake and Mrs. Belladonna.
Anyway, awesome episode, glad to see my fav back, and I hope they keep up the quality

In general, I thought this episode was very good, mainly because of all the plot development.

~What is going on with farm boy (Oscar)? He looks into a mirror and...Ozpin's voice says hello?! For some reason, I just thought of a weird theory that Oscar could be the new Spring Maiden, but he's, well, not a maiden, so...idk XD

~I was excited to see Raven appear (and play a big role!) in this episode because I was always unhappy that her storyline was always hinted at but was never fully developed or resolved.

~Not sure how I feel about the whole thing about Yang's bionic arm--I just kinda feel like everyone else is trying to force it on her, and I thought she had a really good point when she was talking about how her life without her right arm is her "new normal".

~Team RNJR seems to be taking a backseat this volume, which I actually don't mind. It's nice to have more development of and focus on other characters (ex. Raven and Qrow). RJNR do seem kinda oblivious to what's happening around them, though (ex. Qrow killing all the Grimm for them), plus Ruby and Jaune especially are wrapped up their own grief. So we'll see how that turns out.

~We didn't see any Blake (or Weiss) this episode >.< Crossing my fingers for next week!

Okay, Raven, we need to talk. I understand you're trying to do your whole "dark loner heroine act" over here, but goodness woman, you daughter's ARM WAS CUT OFF BY A TERRORIST THAT TRIED TO KILL HER BEST FRIEND and all you care about is some stupid relic? I know she's trying to do that right thing but geez.
And about Yang... Oh my poor summer child, I feel so bad for you. That dream that the beginning was awful. I have a feeling it's gonna take a while for her to get used to the arm. I wonder if she'll keep using Amber Celica. Probably. Defininetly. 
And I think Ozpin is hiding in Oscar's barn, either physically or as a disembodied ghost. Are there ghosts in the world of Remnant? 
And I think it was interesting how Qrow's been following RNJR and killing the Grimm. There's likely so many because, well, a bunch of hormonal teenagers are roaming a country they're fairly unfamiliar with and have seen their best friends killed or seriously injured, a school they pretty much called home brought to the ground, and they probably think the man they looked up to and respected is dead. And Grimm are attracted to negative emotions. You do the math.
Overall I love this episode. Only complaint is that I wish wend gotten a bit more of RNJR, Blake and Sun, and Weiss, but they'll likely be back next week.

I LOVE BLAKE'S PARENTS. Kali and Ghira Belladonna are both really good characters. I'm happy I was right about Blake's dad not liking Sun (because of course hems gonna be suspicious of a guy who hangs out with his daughter so closely), and him being really sweet to Kali and Blake. The whole scene at dinner with "She's got the moves" was probably the funniest part of the series so far. I'm happy that at least one RWBY member has a stable home life (not saying that Taiyang Xiao Long was a bad parent, from what we've seen he's nothing but loving and protective of his daughters and knows them very well, and he likely did the best he could by himself. But growing up without a mother was obviously tough). Ironically it's the most cynical and jaded member of the team.
I wasn't sure what to think of the White Fang dudebros, but OH SNAP ADAM MIGHT BE IN MENAGERIE (speaking of Menagerie, it sucks that it's a sort of nice island but they're all crammed on it due to desert).
I hop that that creep doesn't come after Blake.
DAT BOI LOOKING FOR RUBY IS BACK TOO. He's fairly close on their trail as well, I wonder what will happen here.
All in all, fantastic episode, my only complaint is that I wish we could have seen how RNJR is doing (we haven't gotten an episode that seriously focused on them since the second one) and more about Weiss as well (again, haven't seen ANYTHING from her since episode two).

I think this is actually the best episode of the season so far. First off, we finally got to touch base with Team RNJR again and got some serious focus on Ruby, Jaune, Nora, and Ren. I'm not sure if Ren's parents are dead or what though, that seemed to be what he was implying with his sorry when they got to Oniyuri, but Nora looked sort of surprised and those two have been "friends" (*cough cough* THEY'RE IN LOVE *cough cough*) and you'd think she'd know his parents were gone. That or she was sad for him, I don't really know.
We also got so check up on Weiss again and MAN, can that girl sing. Also her Semblence seems to be flaring up when she's mad. Thanks to that, we got to see JAMES FREAKING IRONWOOD in action again. I think he and Weiss are gonna end up running out to help Ruby and co somewhere near the end of the season. And did that gut flirting with Weiss look a little bit like Neptune to anyone else?
So Tyrian's a scorpion Faunus. That's neat. I liked it when Ruby shot Nora with her electrical bullet and charged her Semblence up, even if they were ultimately defeated... Except then QROW FREAKIG BRANWEN SHOWED UP. I glad he did, RNJR needs some adult supervision, even if Jaune, Nora, and Ren are 18 by now (I'm pretty sure at least) and would be considered adults in the US. 
Overall, amazing episode, and I hope we have many more like it in the future.