Mandriva and its descendant PCLinuxOS also fall into this category. I believe Mandriva is relatively popular in Europe also, being used in government and such.
It seemed surprisingly popular ca. 2007 before people figured out that they were, I shit you not, tampering with the DistroWatch numbers by spoofing hits.
A decent distro though, and it was a little more usable than Mandriva at the time.
Mandriva is less frequently released and like suse fills in gaps with their own technology such as system control centre. They have also been very bad at creating a community which leads to forks like PCLinuxOS and Mangia
I don't quite understand what you mean by "fills in gaps". There are no gaps, YaST on openSUSE is provided in addition to pretty much what anyone would expect on any distro.
Edit: I see what you meant in a comment later/earlier in this thread.