There are already many option calculators around. On-line calculators, off-line calculators, warrant calculators, exotic excel add-ins, esoteric derivative excel sheets, java option applets, they are quite many. Few of them, however, use pricing engines which go beyond simple analytic formulae or 500-step binomial trees. In fact, most of them do not even take account of discrete dividends.
ATOM, instead, lets the user choose among different options classes and among different pricing engines, each with a set of features which are not present in any other calculator. Moreover, while other calculators are black boxes - they do not even state how they calculate Greeks - ATOM documentation at least names what calculation methods are used in those cases which admit of more than one.