This might be the best episode of Brotherhood since episode 19, where Roy took on Lust. In fact, there hasn't been an episode near this good in at least a month.
Okay, so maybe I'm a little biased, seeing as how this episode featured a lot of Olivier Mira Armstrong, Alex's sister, and my favorite female character in Fullmetal Alchemist. She's such a great character, with so much presence. She's pretty brutal, but not cruel, just duty-hardened and determined. She's also extremely attractive, reminding me a little of a young Kim Basinger. You know, circa Never Say Never Again. Maybe a little later, from Batman. I never get tired of her irritated/angry faces, especially when they're played for laughs (her being annoyed that her brother is doing well).
Keep an eye on her, she's obviously not just a pretty face. If she's not a favorite of yours yet, just wait. It'll happen for you.
I enjoy all the detail put into the series at times. Not only just the scenery, stuff like the ice and snow in this episode, which is all beautiful. What I mean is, stuff like Edward's scar still being there on his forehead from a fight he had more than twenty episodes ago. Roy's scar from where he carved an alchemy array to fight Lust is still there the last time we saw that hand. It's little things like that help to immerse the viewer in the world the show takes place in.
We're introduced to Olivier's subordinate Miles in this episode, who has an interesting voice. Actually, it's Kazuya Nakai, Zoro in One Piece. This is a much different voice than Zoro's. Miles has Ishbalan blood, and his revelation of it and what it's meant was a good scene. He's sort of Olivier's Hawekeye. Then there's Buccaneer, who's probably Olivier's Havoc. I bet Olivier could give Roy and his group a run for their money in a fight, even without alchemy on their side.
If I have any complaints about the episode, there are two minor ones. The first is that there lacks any new music in the soundtrack in this episode. You would think with this new arc starting, they'd have Akira Senju compose some new tracks. The second is that the episode ends in a strange place, just before Olivier reveals the solution to defeating Sloth. It's not too big a deal, though. They don't take a lot away from the overall quality.
It's an excellent episode.