I hasten to add, I'm not arguing it's "safe" because nobody has broken it yet, but because researchers have actually taken the opportunity to try to break it and have so far been unsuccessful. (The difference being, I could concoct some random algorithm and challenge people to break it, and in two weeks claim "nobody has broken my ultra secure PRNG" when nobody has even bothered; then I could throw in something lame like, "and I did some statistical analysis which showed a random distribution, so it must be secure." This is how commercial companies and bloggers sell their snake oil.)
Also, over the years the maintainers (like Ts'o) have improved things when actual issues were pointed out.
That's not to say it won't be broken tomorrow, or that it's as good or better than, say, Fortuna.