What are the pros and cons of using Acquia Drupal install packages?
Boris Mann once described Drupal as a big box of Lego. Acquia Drupal is just a bigger box of Lego.  It still doesn't do anything out of the box, it just gives you more pieces.  Given how much stuff went into Drupal 7 core it is mostly redundant - download core, views, wysiwyg and admin and you can start building good sites.

In terms of pros for Acquia Drupal I'm struggling a little.  The first is that it helps inexperienced users get onto the Acquia Network.  The other is that you don't have to download everything, but this is also a con as you get everything Acquia thinks you need.

One of the biggest cons as I see it is that they dump all the modules under modules/ which is considered bad practice in the Drupal community.  Not only is this annoying if you decide to switch back to stock Drupal + contrib or Pressflow + conrib, but it teaches users bad practices from day 1.

I must admit I played with it once and decided against using it.  These days I assemble my code using drush make as it gives me only what I want and I'm not dependent on a third party to provide security releases after a module is updated I can just update my make file and reroll my stuff.

[rant]These days the community has moved on to building true distros, not just throwing more Lego pieces in a box.[/rant]