I worked with wp-e-commerce and shopplugin and tried WooCommerce for my latest project. It is very developer friendly, almost bug-free and working with developers and translators via GitHub has been a breeze. Totally different to what I experienced with the other ecommerce plugins.
Totally agree jessor. WooCommerce is awesome, the support is fantastic. I’ve been in ecommerce for close to a decade, and have really come to admire the simplicity and flexibility that Mike and crew have created. Yes, there are situations where you may want something different, but honestly, for 99% of business, especially ones using wordpress, WooCommerce is top of the list by miles.