Group: V 2.47 release
This used to be fine with the old bevel script (Blender 2.44 and below)... I'm really unhappy with how bevel works in recent Blender versions (e.g: Blender 2.46, 2.47).
Newer versions of bevel can not treat a mesh whilst maintaining...
...Number of edges: three for each previous edge (minimum needed for smoothing).
...Number of triangles: none.
See attached image or http://img402.imageshack.us/img402/8651/bevelprobak3.jpg
I did the left cube on an older version of Blender by beveling twice. Newer versions can't reproduce this geometry. I think they should because it...
* creates no triangles
* is non destructive to edgeflow (e.g when later inserting new edgeloops
* has the ideal minimum edges for maintaining edges on smoothing (two has lost the edge, whereas four is excessive).
The problem seems to be caused because dragging the bevel width halts when two vertices meet up, whereas in previous versions, they would clip and allow for further dragging to sandwich the edges flat. This allowed for closing the seam instead of using four edges. Extra vertices could then be removed with "remove doubles", but even that was rarely needed.
An alternative fix would be to include a checkbox for "keep previous edge" in the current bevel function, with allowance that the prior edges should shrink a fraction to respect the bevel curve.
Other than that, I'm finding it extremely time consuming making my bevels by hand in order to meet the modeling requirements of my clients & other colleagues.
Please look into this, as it's going to make my modeling with Blender a lot easier once fixed.