V3Beta
Release notes for each V3 beta release are gathered here.
Aug-24-2011
New Flow command (Transform > Deform > Flow, no icon yet) for deforming objects from one "backbone" to another, some examples in these forum posts: [1] [2]
New selection indicator in the scene browser - shows a yellow dot on the right hand side to show if an item has selection or not, also now click on that spot to select or deselect things in the scene browser. Also you can use Ctrl+click on that same spot to set a selection filter which is also new. Some more descriptions here: [3] [4]
Major overhaul to many internals - the UI is now based off of WebKit/JavaScriptCore instead of mshtml.dll/JScript.dll , updated to new OpenNURBS v5 library for reading 3DM files - this enables reading of Rhino v5 files and should round trip stuff like extended layer properties to Rhino v4 better. Also updated to the newest release of the Solids++ geometry library which has some various bug fixes in it. There may be some regressions due to all this various library churn, let me know if something that worked in v2 doesn't seem to work in v3.
10-25-2011
New Twist command (Transform > Deform > Twist, no icon yet) for deforming objects by twisting them around an axis line. Some examples in this forum thread: [5]