The premise had potential, the acting is fine, it looks good, but Buddymoon isn't funny and really isn't all that interesting. If you have a good friend you like to joke with a 2 hour car ride through the country will be more enjoyable and funny.
The most interesting part of Buddymoon is the character Flula, a German man who has a humorous, bright personality. But a lot of his lines an malapropisms seem forced which makes the character feel artificial.
If you're sick on the couch and just want to watch something pleasant and not challenging Buddymoon isn't a bad choice. (I kept watching the film mainly because the two main leads were good looking.)