Here some of the benefits to using the new ga.js code.
- Faster, smaller source file
- Automatic detection of HTTPS
- Increased namespace safety
- More convenient set up for tracking e-commerce transactions
- More customizable code for interactive Ajax-based sites
- Ability to take advantage of the most up-to-date tracking functionality as it is added to Google Analytics
- Advanced Segmentation Reports
- New GUI for report center
- Custom Segmentation
The only downside is that filters can still only be applied for new data, and old data cannot be reprocessed.