Difficult. Very difficult. As mentioned above, the new movie (plot and songs) follows the book better. The old movie didn't really... Well, the environment was less lovable. The Oompa-loompas were kinda odd and the factory itself looked a bit iffy. But that was the style back in those days.
Also, Johnny looks extremely
hawt awesome as Willy Wonka. Howeverrr... This new Johnny personality doesn't match the book at all. Don't get me wrong, it's a wonderful personality. I love the psychopaticness. However, it just doesn't say... 'Willy Wonka'. So you have to give the old movie credit for catching it properly.
Hmmm.... Well, it's a tough choice, but I'm going to go with the new movie. Though if Johnny was less of a Psycho and more of a Willy, it'd have been an even more obvious choice.
When asking me which Wonka I like better, not comparing it to the book... Hmm... I'd say Johnny's Wonka. The whole dentist story just fit so nicely.