From the Ruby Documentation: http://www.ruby-doc.org/stdlib-1.9.3/libdoc/pathname/rdoc/Pathname.html#method-i-join

path0.join(path1, ..., pathN) is the same as path0 + path1 + ... + pathN.

```+``` is implemented on Pathname and is shorter than ```join``` in this case. So I would go with ```+```.