I've got memories of some of the Snowy Mountains scheme's hydroelectric generators being designed to start though self-excitation.
Wikipedia also has a bit about it [1]. It seems that there is usually a backup facility to run a DC current though the field winding before starting, thus magnetising the magnetic paths, for when the residual field has decayed too much. That backs up your comments about reliability.
Residual flux is usually enough to start, but if you lose all flux for some reason (when the core is completely demagnetize) zapping it with DC can help restore it.
Wikipedia also has a bit about it [1]. It seems that there is usually a backup facility to run a DC current though the field winding before starting, thus magnetising the magnetic paths, for when the residual field has decayed too much. That backs up your comments about reliability.
[1] http://en.wikipedia.org/wiki/Self-excitation