I think that Anna Karenina is a very good novel, in fact I would go so far as to put it in the top five of all time, but do I think that it is the best novel of all time? Not at all. I think that honor belongs elsewhere.
Anna Karenina is a great novel with all of the characteristics of being a very awesome story. But I disagree with the assumption of it being "the greatest novel of all time" there are more even great novels out there like "Out of the Night That Covers Me" or "Pride and Prejudice".
No, I don't think that Anna Karenina is the greatest novel of all time. It is great, but greatest? I think that something like that is hard to judge. But if people were to judge, I really don't think that Anna Karenina is the novel most would choose as the greatest.
No one novel is the greatest novel of all time, because the subject of a novel means different things, and has different levels of meanings, depending on a reader's personal experiences, proclivities and desires. It is one of the greatest novels of all time, but is not the greatest novel of all time; no novel can hold that title.