Ever since the word Symfony was first whispered on IRC there has been a lot of anxiety in the Drupal community about how much, and what kind of effort will be needed to port a contrib module from Drupal 7 to Drupal 8.
Personas are an insightful deliverable to help create better user experiences. They can be approached a number of ways depending on your end goals—whether you're redefining your brand voice, informing your product development or providing guidance
Using virtualized environments for development is smart. You can create accurate replicas of arbitrary systems, safely isolated from your host OS and other development environments.