Some companies even have Git, Mercurial, and SVN, working all together under centralized repository management.
Both git and mercurial can talk to "non-native" remote servers.
IIRC mercurial can talk to subversion and git (with hg-git).
Git can talk to subversion, cvs, perforce, mercurial (there are multiple tools for the latter, and I'm the author of one of them), bzr, and maybe others.
If things don't work smoothly in any of those cross-VCS configurations, my belief is that issues should be filed and fixed.
Working in a big firm adds overhead, yet has certain benefits (resources, etc.). That's a whole different topic though.