Should we start using Package builder and installer to move sites from development to production?
In general you should continue to use MSM to migrate implementation between development and production.
MSM is designed to operate between two very similar servers, such as a development server and a production server, and to keep those servers in sync by reliably deploying new implementation from one to the other. The Percussion Packager is designed to allow repeatable and reliable deployment of reusable implementation from a single source system to any number of different target systems, each of which may have fairly different existing implementations. The Packager’s configuration capabilities enable integration of that new functionality seamlessly into disparate target systems, and allowing for installation and upgrades of these packages without needing to modify existing implementation.
The two different purposes of these tools has resulted in design decisions such that they are not necessarily interchangeable. There are various types of implementation that can be deployed using MSM that were not appropriate for inclusion in the capabilities of the Packager, and the automated dependency management of the Packager would not generally be appropriate for use in the type of deployment scenarios for which MSM was designed.
I found a little information on the Package Builder by watching this webinar near the end, unfortunately it’s a progressive stream so you can’t skip ahead (http://percussion.com/web_resources/www.percussion.com/media/video/Percussion-CM-System-6-6-and-6-7-Webinar.wmv). I am pretty sure there was going to be a webinar on the topic but I couldn’t find it listed on their upcoming events.