This shopping cart is much more than just an extension to help you sell your products but also very integrated complete sales, shipping, payments, users, orders, more more more management system. So many features had been included into it that it is becoming number one shopping cart on the web (imo). Because of complexity of code and lack of volunteers project was a bit weakened for a while, but now it is back and rocks better then ever.
Some of my favorite feature are easy and extensively complete administration of all customers, orders, shipping options, payment modules, coupons!, product types and attributes, etc...
Remember, that it was created mostly by a single person and new joining developers have to learn tons of code that is why updates are not too often but improvements are tremendous!
Thank you for COMPONENT #1!

I used this extension to run a showcase on my front page and it works perfectly. The load on proceccor is light, code is simple and neat, CSS is easily customizable, from all the slide-show extensions currently published on this website, this one is FREE and really working plus nice documentation available on developer's website.
Very recommended.