New User Features
UI refinements for simplicity, speed and power-efficiency
Faster, more intuitive text input (redesigned keyboard and text input)
Improved power management
Control over applications (Manage Applications – running tab)
New ways of communicating, organizing (NFC, VoIP, SIP)
Downloads management
Camera access (front and back)
New Developer Features
Performance
Concurrent garbage collector
Faster event distribution
Updated video drivers
Native input and sensor events
Gyroscope, rotation vector, linear acceleration, gravity, and barometer support Improved 3D motion processing
Open API for native audio
Native graphics management
Native access to Activity lifecycle, window management
Native access to assets, storage
Robust native development environment
Mixable audio effects
Support for new media formats
Access to multiple cameras
New Platform Technologies
Media Framework
New media framework fully replaces OpenCore, maintaining all previous codec/container support for encoding and decoding.
Integrated support for the VP8 open video compression format and the WebM open container format
Adds AAC encoding and AMR wideband encoding
Linux Kernel
Upgraded to 2.6.35
Networking
SIP stack, configurable by device manufacturer
Support for Near Field Communications (NFC), configurable by device manufacturer
Updated BlueZ stack
http://www.youtube.com/embed/Jx3pdWBlZ34
Source: thinkdigit.com
Disclaimer: could not find post which details out benefits of Android 2.3 Gingerbread hence posting, if this is redundant mods do delete.