Digital / Downloadable products recommendation

I reckon there are three main e-commerce plugins for WP; WP Shopp, WP e-Commerce and Cart66.

Does anyone have a recommendation as to which handles digital (downloadable) products the best and with most functionality?

The ability for the user to login and visit their repository and download their purchased products would be ideal. The facility for purchased products to have an expiry in which time they can be downloaded X times within Y days.