I think any Jungfrau area base is sweet - Lauterbrunnen fine but the town that Fodorties like the best seems to be Wengen - for its marvelous views and car-free smaller town village feeling - unlike brash Lauterbrunnen, home to some huge camps of young student tour groups which makes the town lively - many like the eerie quiet of a Wengen. Me I would prefer Lauterbrunnen and have stayed there several times but what base is best for you is a factor of your age and what you want to do at night, etc.

I am not sure when you are going and it will probably be a faded memory by the time you get there but I just saw where there was a major mudslide in Hallstatt June 20th that was triggered by a big thunderstorm.