Great job.

I did a side project that helps with comparisons, but in a rather different way (e.g. how many African elephants does something weigh). Not as slick as this site, but someone might find it useful:

http://howmanyelephants.co.uk/

Nice. Two quick UI thoughts. Upon loading, perhaps start with some unit selected, and a default amount 1, so there's immediate content to be seen? And to extend the experience, maybe add a "dice roll" button, so users can "see more neat things" click-click-click without the cognitive overhead of pathing the option space