Richard:
Tom may have more to say about this, but I heard
in a presentation at NCURA that faculty often
jump on the opportunity to file a provisional without
realizing that the claims outlined in a provisional cannot
be changed in the full. So there is a drawback in that
if the project changes substantially in that 12 months
(it may, if still in the developmental stages), then
the full patent claims cannot be expanded, thereby
potentially limiting the protection extended to the
invention. Hard to tell faculty members (particularly
those with eager brothers!) that a provisional may
impose limitations down the road.
Best of luck,

RJS