
The Ultimate Drupal Power Tool!
This is an absolute must have module for any developer. Devel can help you track down bugs, find out why your site is slow, discover how things are themed, learn what functions are being called, generate random content, clear your cache, switch users on the fly, view every SQL query, where it came from, and how long it took to run... and more!
This module has so many useful features, it's unbelievable. Devel is the ultimate Drupal power tool, and you won't get far without it.
But with great power comes great responsibility. This module has the ability to wipe out all your content, among other things. A great tool for your development site, but use strong caution when dealing with a live site.
Review by John [info] on May 13, 2009 - 13:31

Simply must have for developers
I probably wouldn't suggest non-developers install this, but if you are a developer or a Drupal6 themer, it's a must-have.
Review by Harry Slaughter [info] on April 4, 2008 - 01:37

Developer's tool
I couldn't resist to rate it because I frequently use it.
Review by vrencianz [info] on March 27, 2008 - 15:50

Firebug for Drupal
The devel module is a great help understanding how Drupal works, finding the functions you need to override to customize Drupal, identifying performance issues, theming Drupal etc.
There are still issues with the Zend Optimizer and the latest version of Devel, I recently experienced on a shared hosting system.
Review by yaph [info] on March 17, 2008 - 20:36