New Relic performance monitoring and the Features Module
By design, Features shouldn't induce any performance hit besides what is inherent to any Drupal module.  It doesn't implement hook_init() or hook_boot(), nor does it implement any hook_form_alter()s or Node API hooks, so there should literally be no Features activity on most page loads.

However, every time caches are cleared, Features does some heavy work — it interrogates all Feature modules and rebuilds Faux-Exportables.



There are two kinds of Features Components: Exportables and Faux-Exportables.

Exportables

Anything that is a CTools Exportable is also a Features Exportable, such as Views, Contexts and Panels.

On this issue thread, one of the Features maintainers says:


  Generally speaking a View in the database and a View in code perform exactly the same. There are some slight differences in loading methodology (it helps to have a good PHP code cache like xcache or APC when using exportables as the data lives in code), but other than that you shouldn't see any differences.


Faux-Exportables

Faux-Exportables include content types, CCK fields, taxonomy, roles, and permissions.

Faux-Exportables are by definition stored in the database, so they do not require any intervention from Features.  Features only touches Faux-Exportables when rebuilding (as mentioned above).