I found a review of the 6100 on Photography Blog
this morning. It is a nice overall review of the printer but does not get into detail on whether the 5000's deficiencies - paper path selection, black point compensation, etc. - have been corrected. There is a reference that indicates that the documentation is of a higher quality but no reference as to how well the documentation covers the details and specifics of the available printer settings.
I will certainly be awaiting Michael's review.