As a developer, I've tried every major shopping cart plugin available over the years.
WooCommerce is by far my favorite WordPress shopping cart. I wish I had found it earlier.
For the page styling, the template system makes it easy to customize everything without losing plugin update ability. When I have a client on a budget, I can use the default cart styling and it looks really good right out of the box.
As far as the cart functionality, everything works great on both the frontend and backend.
My clients are able to quickly learn how to add and manage products and I've not had any complaints from them. If you have products with variations, WooCommerce can handle those with ease. WooCommerce product variation support is unparalleled.
For customers, the browse, add to cart, and checkout process flows smoothly. I have not had any complaints on that front.
I have purchased a few of the premium extensions and the support team has been very prompt and helpful when I needed help with those.
Thanks to WooCommerce, I no longer dread meeting the clients that need an e-commerce website.