I was exposed to Mercurial before Git and I stubbornly tried to advocate for it over Git for a while. BitBucket, at the time, gave Github a good run for their money and had great Mercurial support and was what I preferred.
I'm not really sure VCS were ever differentiated for there to be a wide world of them. They all solved the same set of problems so similarly that it felt, to me, that there had to be one winner. Right now most of the competition is in the Git Porcelain space.
N.B. I actually have a soft spot for darcs, which was my first actual DVCS. I just loved it so much more than svn and refused to use svn in college and used darcs to actually manage my projects and push them to svn after.