The Brothers Karamazov seemed bizarrely overrated, particularly compared to Dostoevsky's other work. For the first two Parts it was very powerful, but Part III was relatively dull and Part IV was almost completely stagnant and uninventive.
The introductory character portraits were fantastic, but the character development, with the exception of Dmitri, was pretty much nonexistent. The writing also becomes painfully didactic whenever socialist characters speak (Rakitin, Krasotkin).
The first couple acts were filled with excellent scenes: Father Zosima blessing the peasant women, Ivan's poem about the grand inquisitor and his arguments against Christianity, Alyosha's conversation with Snegiryov, the meeting with Zosima at the beginning of the novel, Fyodor Pavlovich talking about how he abused Alyosha and Ivan's mother, and several others. In the last couple acts there are only two or three episodes on par with any of these.
At first Alyosha is a very distinct, interesting character, but in the last two acts he becomes an errand boy whose personality has limited bearing on his interactions. Illyusha's disease is, for the most part, tactlessly sentimental, and Krasotkin's ideological salvation is perhaps understandable because he's 13 and thirsty for respect, but still pathetically lazy in terms of set up and writing. Ivan barely shows up in the second half of the book, his meetings with the crippled girl are unexplained, and he ends up in a completely unresolved state, without really even being ideologically confronted by other characters. The meeting between Ivan and the devil was very disappointing, too. Katya is a cunt.
Also, the prosecutor's speech is practically 25 pages of recap. Defense attorney's speech was excellent, and was the highlight of the fourth Act in my opinion, but it was a pain to get to.
It was also thematically unfocused, and basically was a package of a bunch of Dostoevsky's reactionary ideas that didn't come together cohesively or unify in any sense, much like the subplots different characters had.
All things considered, Crime and Punishment was much, much better.