They are all reasonable cars, so you need to pay close attention to service history and condition. As a rule, Honda is one of the best brands in the world for reliability and the Germans have relatively poor records, but every car is different and it will depend a lot on how it has been looked after up until now.
With the Volkswagen or Audi, you should check to see if they are affected by the Dieselgate recall scandal. If they are due to be recalled, or if they have had the ‘fix’ applied, I’d steer well clear as there are too many reports of problems with these vehicles.