I have not done a detailed low-level review like that no - that would
require way more time than I have :-)
I have however used it for over a year now, in production, without any
major issues or incompatibilities. Some minor bug fixes here and there,
that were contributed upstream (mostly SELinux related). But I do not
believe I have double-fork services - do you have a particular one in
mind? I could do some quick testing.
More importantly, I think it has been the default for Fedora since last
year. That ought to be enough battle-testing for us to provide it as a
option :-)
I also know many Orca screen reader users who rely on d-bus broker
without reporting downside, they report an improvement in
performance. They are both in Fedora or in Arch Linux. Orca relies
only on d-bus to receive accessibility notifications.