Some of the members of the Debian Technical Committee are starting to post their conclusions regarding which init system the distribution should use in the future. In particular, Ian Jackson has come out in favor of upstart: "Firstly, unlike the systemd maintainers, I think portability to non-Linux systems is important. It may be that our existing non-Linux ports are not very widely used, undermaintained, and/or not of production quality. However, I think it is important for us to keep those options open."
Russ Allbery, meanwhile, is in favor of systemd. "There are two separate conceptual areas in which I think systemd offers substantial advantages over upstart, each of which I would consider sufficient to choose systemd on its own. Together, they make a compelling case for systemd."
In both cases, the authors have extensively documented their reasons for their decisions; reading the full messages is recommended.