iCalamus has lately been an amazing app: maximally exploits MAC OS X capabilities (that is why its developers clearly state it is and will be a MAC OS X-only app), with an abrupt blast on the market. It has not yet solved some preoccupying issues, e.g. footnotes import (most important to me) and some others things, did not initially run in Leo, but now it does...
iCalamus is just a step from becoming a great app, this is the great temptation of a small company on the brink of becoming a great company. But will European (small) software companies ever become decisive on the market?