Linux - Elementary Lune (12.04)
Core I3
Nvidia GeForce 9600GT
2.69 and previeous versions
The scale of the scene seems to effect the way the camera can be moved. In the Preview view Moving the mouse-wheel makes the camera jump in large increments within the scale. If you use Mouse-Wheel-Button + CTRL the increments are slightly better, but very hard to control as they aren't smooth increments.
Sizes bellow 12" inches (30cm) seem to be the hardest. The size of a Rubiks cube is a good example too (approx 8cm) - very hard to position camera through the view.
Additionally there are many occasions that the camera appear to not want to zoom in anymore, stopping before the object. To fix I tend to have to move the camera manually in another view to fix it - this could also be part of the same issue.
These issues have been around a long time, since 2.5 I think.
Thanks.