The first thing I check for when assessing a chemical structure editor is how well it copes with radical species. Sure, you can usually draw ethane (CH3CH3) in a couple of clicks, but what about an ethyl radical (CH3CH2.)? Don't forget us combustion chemists! Importing, exporting, and translating such species from format to format cause no end of trouble, so at least I want to be able to draw it and see it. That's the first thing I *check* for, because things like speed of loading, usability, prettiness, all smack you in the face without checking for them. - Richard West