Easiest Shopping Cart Plugin

I searched in the forum for an appropriate answer to my question and couldn’t find any. This is why I’m posting.

I need a shopping cart plugin to sell digital products including pdf’s, mp3s and video.

I liked shopperpress but it requires you to change your whole theme. I don’t want a theme change.

The only other one that looks worth trying is wordpress estore.

How about you? Which plugin do you like working with?
Which one can be implemented quickly?
Which one has good support?

Thank you