Don't worry about the length or the huge cast of characters as you read. You will get accustomed to all of the many characters and you will begin to see the book as an old friend waiting to be read daily. The social exploits of the characters are vividly interesting and intriguing. I feel like I have been to Russian drawing rooms, wars and theatre.
Although I prefer War and Peace to Anna Karennina, I would recommend Anna to anyone who wants a bit more philosophy and less history from Tolstoy. It may also behoove the reader to purchase a book or two that explains the historical info regarding Napoleon's march into and out of Russia as a companion to the reading of War and Peace. I used one with biographies of French and Russian generals as well as battle maps and understood the war scenes much clearer.