I did the hardangfjord in a nutshell trip in August 2013 as a day trip from Bergen and couldn't recommend it highly enough. Indeed Norway in a nutshell offers more spectacular landscape but I found that the entire experience of transiting from one mode of transport to another with literally hundreds of other people on overcrowded buses, trains and ferries a big downer to the trip. In contrast, hardangerfjord lets you experience the breathtaking beauty of the fjords in relative peace and tranquility. The picturesque little villages dotting the fjord are worth stopping at. In Eidfjord, I strongly recommend doing the bus ride to the Voringfossen Waterfall which is simply spectacular.
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