Mass hosting best practices for source code management of CiviCRM platforms?
I like that drush make or composer reduce the amount of code in your repository, and encourage IMO better development workflows (eg submitting and documenting patches rather than forked codebases).

However I am also running into challenges using Drush, which is quite Drupal-centric and requires some working around rather than with if you don't do what it expects (profile modules to profiles/ folder etc).

Best of both worlds if you build a deployment branch which is the complete codebase, but it does require that the whole team is OK with patchwork and building - this may be a factor.

Two nights ago I noticed that deploying CiviCRM codebase via Git had a cost of an extra 100MB per site (plus some). Not the biggest cost, but may be a factor if hosting many CiviCRM on a server.