I've been using WooCommerce for almost a year now and haven't yet written a review! I just finished integrating a plugin I built for WooCommerce with a few other systems and I have to say that the WooCommerce code is by far the cleanest and easiest to comprehend. The whole system is built right and I wouldn't run an E-Commerce store on any other system (with the possible exception of EDD for digital downloads). Excellent work, and I'm looking forward to developing more plugins for WooCommerce.
Also, I've heard some people complain about the fact that many extensions cost extra money. Personally, I love the model. It gives the site owner the ability to pick and choose the functionality you actually need instead of giving you a bloated piece of software that slows down your system. I'm more than willing to pay a couple of hundred dollars to get the site I actually want with the features I need.
Keep up the good work!