As other users suggested before .. get the uncut version. It's over 5h long. Get anything else and you will be missing out on something ..
Besides, I would suggest not to rest too much on the fact that Buchheim was disgusted with the film. Buchheim seems to have been very unhappy with the impersonation of himself (Herbert Grönemeyer a.k.a "Leutnant Werner" a.k.a Leutnant Buchheim), imo one of the weakest actors of the movie, as well as the role of Kapitänleutnant Lehmann-Willenbrock, a person that Buchheim seems to have been extremely fond of. Lets not forget that this was basically the story of his life, and after having read Buchheim's novels several times, I must say he seems to have been a somewhat quarrelsome person.
Anyway, imagine what this film might have turned into if it had been made in Hollywood, only then you can give the deserved credit to Wolfgang Petersen. In his hands this turned into one of the best war movies of all time (many claim it to be the best), and besides you get to see some of Germanies finest actors of the 80's in one film.
If you have not, you should read the novels. Don't forget there is "Die Festung", which is a 1000+ page continuation of "Das Boot" during the chaotic events in 1944. So lots of stuff if you're a Buchheim fan. Imo Buchheims style makes him one of the best writers I know, he might have become more popular if the german media had not labelled him as "revisionist". Mind in germany that happens to everyone who writes about the war and not apologizes in every second sentence.
Of course it's advisable to read the german original, if you can. I am a bit afraid the translation could be as bad as the subtiltles in the movie, which are extremely lame. In the original they used words of abuse in every second scene, but for the translation they seemed to have deemed this "too unbritish"
I 've read "Das Boot" at least 3 times, the "Festung" twice, and I 've watched the movie at least 10 times, so much that I know it by heart now
