After going from Joomla to Drupal, trying Wordpress, I eventually came back to my old love, Joomla. I needed a shopping cart and I looked into several ones and choose for MijoShop. This was a perfect choice. I am having such a great experience with MijoShop. The support team gives very personalized support. Their ticket system works very well. They even helped me deciding on 3rd party extensions. Such a wonderful service and that within a very short time frame, even though they're in Turkey.
The product itself is easy to install and based on OpenCart. You have to study OpenCart but that wasn't difficult at all. There are tons id extensions, for most what you want. Free or Commercial.
I strongly recommend this product.