I have never seen English translations of Tolstoi or Dostoyevski, but I think the stylistic differences are really blurred in them. In the original, the difference is great: Tolstoi is "light" and "life-asserting" while Dostoyevski is more "gloomy" and difficult to read. "Anna Karenina" is one of the best books I've ever read (not only in the Russian literature).
As for Dostoyevski, I once liked a phrase of a critic: "He uses a really specific way of narration. He doesn't use as many vivid expressions as Tolstoy does, and his language is not so beautiful, but he creates the atmosphere with slight speed-ups and slow-downs, alternation of aggressive and calm speechs etc, which is not so noticeable at first". Try to read "Crime and Punishment" in English once more keeping it in mind - and it should be interesting if you notice it.