Asiatics are unscented,multiply quickly and are very easy to grow,they also tolerate most soils.
Orientals are scented,they tend to be more difficult and they multiply slowly,they do not like lime rich soils.
Rich

Asiatics also bloom earlier than Orientals, at least in my experience. Planting both, along with some Trumpets, gives a succession of bloom, generally: Asiatics -- Trumpets -- Orientals.

go to www.lilynook.mb.ca. It will give you an excellent explanation of the various kinds of Lilies. It's a Canadian web site from Manitoba.