Now it seems to be OpenSUSE's turn. The discussion I link to here doesn't make any definite conclusions but they seem to lean towards NSS as well, claiming it has the most features. I wonder what they base that statement on - if there's a public doc anywhere that state exactly which has what that makes any contender better than any other for them?
In the Fedora case it seems they've focused on the NSS FIPS license as the deciding factor but the license issue is also often brought up in this discussion.
I've personally been pondering on writing some kind of unified crypto layer that would expose a single API to an application and handle the different libs as backends, pretty much the same way we do it internally in libcurl at the moment. It hasn't taken off (or even been started) since I've not had the time nor energy for it yet.