No ... I personally think that the DVD-R people were upset that the DVD+R people got DL recordables out before they did, now they want to release something .... anything, regardless of how useful it is, to safe face and maybe get a small amount of royalties.
DVD-R DL seems like a dead technology because it is too late and too incompatible with existing standards.
The funny thing is, none of this will matter unless dual layer media prices fall significantly more.
I would not choose a particular drive over another one just because of its DL -R capibilities .... just as I have never chosen a drive over another because of its DL +R capibilities.