Big improvements - This software has been used extensively in production of the Durian open movie project "Sintel".
Feature complete - Although some of the 2.5 targets have been postponed, such as multi-window support showing multiple scenes, a full RNA data level dependency graph, or radial menus.
Exciting improvements in Sculpting - Faster, much more stable and better brushes.
Missing/Incomplete Features - Although really most of it is there, not all functionality from 2.4x has been restored yet. Some functionality may work in a different way. Some features are still slower to use than before.
Bugs - We've fixed a lot lately, but there are still quite a few bugs. For this second beta around 200 bugs were fixed.
Changes - If you're used to the old Blenders, Blender 2.5 may seem quite different at first. Be prepared to read a bit about this, how to reconfigure things, and learn to use the new built-in 2.5 search functionality
That is the list of new features for the 2.5 alpha, they are now at 2.61, approaching 2.62.
2.61 Change Log
Cycles Render Engine
Cycles is a new render engine that is available next to Blender Internal. It is a raytracing based render engine with support for interactive rendering, a new shading node system, new texture workflow and GPU acceleration. It is still in development, and more production features are planned to be added, this is the first preview release.
Dynamic Paint
Dynamic paint is a new modifier and physics system that can turn objects into paint canvases and brushes, creating vertex colors, image sequences or displacement. This makes many effects possible that were previously difficult to achieve, for example footsteps in the snow, raindrops that make the ground wet, paint that sticks to walls, or objects that gradually freeze.
More features
Camera sensor size and presets, improved image saving, 3D mouse color wheel editing, more translations to other languages, node muting improvements, region drawing tweaks, and many more small changes.
Add-ons
New Addons in this release are an Adobe After Effects exporter, Atomic Blender (Protein Data Bank) file importer, Acclaim and C3D motion capture importers, and Nuke camera animation exporter and importer.
Motion Tracking
Motion tracking support has been added, to reconstruct camera animation from real footage, and composite 3d rendered object into movie clips. A new Movie Clip editor for loading clips, tracking points and reconstructing motion was added. Constraints can apply this reconstructed motion into the scene, and compositing nodes are available for (un)distorting rendered animations or real footage.
Ocean Simulation
Ocean simulation tools take the form of a modifier, to simulate and generate a deforming ocean surface, and associated texture, used to render the simulation data. Ported from the open source Houdini Ocean Toolkit, it is intended to simulate deep ocean waves and foam.
Python API
The render engine API has been extended for closer integration, a mechanism to detect changes in scenes and persistent callbacks were added, the noise module was updated, and easier access to library datablocks was added, along with various other changes.
Bug fixes
180 bugs that existed in previous releases have been fixed!
http://www.blender.org/development/release-logs/blender-261/
