If people agree to keep just one binding then i would suggest '%g'.
I appreciate the detailed reply. As I would be fine with either binding, "%g" would work for me. As this is a new command being bound to a new binding, I believe that should not be much resistance accepting that. But let's see if people on this mailing list feel otherwise.
I also like the reasoning for using "%g".
> Unfortunatelly, this symmetry Dired-Ibuffer is not perfect:
there are Ibuffer commands with the Dired 'partner' having
a different binding. For instance:
`dired-mark-files-regexp' bound to '%m'
`ibuffer-mark-by-name-regexp' bound to '%n'.
If there are not many bindings that are inconsistent between the two, it would be nice to sync up the bindings, deprecate the out-of-sync older bindings, and then at some point in future, remove them. But while that's a long process, using "%g" would at least get us getting the dired/ibuffer bindings more in sync.