Here's what I liked about it:
1. Very nice character development and personal growth for Jinta's character.
2. Related to the above, it's good how Jinta's strong points were highlighted well in this episode. It was good to see he's a very effective worker when he wants to be, and that there's a real reason why he was considered a good and likable leader back when he was a young kid.
3. Lovely relationship development between Jinta and Anaru. I like how its believably and gradually building up. I don't
need to see any conclusive romance in this anime, but it would be a nice added bonus.
4. The overall handling of Menma's diary and associated flashbacks was just about flawless, I felt. Really worked well, and had a solid emotional impact. This was helped by the fact that...
5. Menma did
not cry this episode.
YES!!! Finally. 
Granted, she teared up a bit, but at least she didn't release actual water-works this episode. For me, taking a more subtle approach to the emotionality of a couple key scenes actually make them more effective. They felt less forced, and hence more authentic, to me that way.
All-told, a marvelous episode, with another good cliffhanger moment for this anime.