Ironlak and Montana are completely different.
Ironlak is low pressure. Ironlak is awesome and easy to piece with, smells good, clean, good coverage.
Spanish Montana (the only Montana worth using, in my opinion), has both low pressure and high pressure paint. 94 is low, Hardcore is high. Good coverage, nice and thick, and an awesome set of colors. The reason we don't usually see Montana around here is because it's expensive.
We're all Kilz and Rusto.
I'd take a free box of Hardcore before a free box of Ironlak any day though.