New Features :
- Widget Apps
- Tab Stacking
- Safer address field
- Opera Extension
The other stuff is Tab Stacking... I use it so you can save your space if you open a multiply tab when browse.
Load on demand for flash video also a good one, so it don't eat that much RAM like the other browser. And i must admit that it fast enough, especially if you have a slow connection you can enabled opera turbo feature which can compress an images on the fly.
Try it, safer - faster - lighter