Thanks all...
So from what I have learnt then bundles files aren't buggy.
There is a disadvantage however:
1) Statistically you may have more chance of recovering from a project then a bundle.
2) Bundles "force you to render or discard Audiosnap edits."
* Advantage of bundle file however:
1) Easy portability.
2) Compact.
3) Defragments audio data
**http://www.cakewalk.com/Documentation/default.aspx?Doc=SONAR+X2&Lang=EN&Req=AudioPerformance.23.html Interesting....
* Apparently a ZIP file can do this which begs the question why aren't bundle files at least as good as a ZIP?
I can see the advantage of not saving audiosnap data but it should at least be an option.
** Wonder why there isn't a facility to do this in Sonar anyway without having to make a bundle file.