When I read the title of this thread, I thought it was a joke. I've never heard of such a phenomenon as "Parker 51 disappointment". It is, without exaggeration, the single most fuss-free, dependable pen in my lineup. Admittedly, it's a Special (so not a vac - an aero, rather) so filling is more obvious. But it just writes like it was made to do it (hey, would you look at that).