Hi Mike, the main new tools for the next v4 beta are annotations like dimensions.
A few screenshots of some earlier stages here:

http://moi3d.com/forum/index.php?webtag=MOI&msg=9363.107
http://moi3d.com/forum/index.php?webtag=MOI&msg=9363.108
http://moi3d.com/forum/index.php?webtag=MOI&msg=9363.95
http://moi3d.com/forum/index.php?webtag=MOI&msg=9363.100

There will also be a new "Detailed object properties" dialog which will have stuff like getting the length of a curve and the surface area or volume of a solid.

For previous V4 betas there is a collection of all the release notes at http://moi3d.com/wiki/V4Beta

- Michael