I've read the book and seen this version several times. The main drawback is of course time.
Thus, it must inevitably slight: a) many of the characters who bring joy to reading the novel - the princely father of the Kuragins, Sonja's story, Nicholas falling in love with Marya, the forgiveness by Bolkonsky (Ferrer) of Anatole Kuragin when his leg is amputated on a table beside which he is lain out, etc. and b) much of the philosophy contained in the book - whether about the masons or the purpose of life.
However, as a sort of highlights version of the novel, I thought it dealt well with the main lines of the plot.
It also is clearly 1950s film-making. There is little sense indoors of the lighting of the time, the sets look generally clean or deliberately destroyed (rather than mysterious and gloomy). In fact, the entire film appears all too clearly delineated - there is little of the kind of murkiness one would find in such a movie being made today - say, the way Schindler's List looks - or The Last Emperor looks.
The movie is also benefitted by having Audrey Hepburn, Anita Ekberg and John Mills - physically they are EXACTLY what I imagined of these characters - and I thought Mills and Hepburn were excellent. (And what Ekberg lacked in ability to convey emotion, she gained from her jaw-dropping embodiment of the buxom blonde!). The Henry Fonda choice for Bezuhov is an odd one - he's not the first person I think of when I think of a huge heavy awkward bear of a man. He did the best he could but was clearly miscast. Prince Bolkonsky (the father) and the Count and Countess Rostov were first rate - so were the choices for Napoleon, Homolka as Kutuzov, Kuragin, Dolokhov and the Rostov family. Mel Ferrer was ok - but imagine, say, the Terence Stamp of Far From the Madding Crowd and how he could have done.
All in all, this is clearly a movie of its time in cinematography, sets, the clearly drawn lines of the script - but it is entertaining and does about as well as possible in dramatizing in 3 1/2 hours a book of over 1000 pages.
