I would go with woo commerce, you only need one extension to be able to get into the closed support forum and chances are you will buy one. A lot of people are moving to woo comerce and extra plugin development is moving very quickly (new ones appearing every couple of weeks in code canyon and on the woo site directly).
Out of the box it isn't perfect a couple of niggles regarding display To me the category display is not ideal,
1. 'arrange by' drop downs are at the bottom when they should be above the products,
2. if you have sub categories they are all set to be inline with the products so if you have say 3 subcategories and are displaying 16 products per page you will have one line at the top with 3 subcategories and a product then a line at the bottom with just 3 categories.
3. You have to implement a paging plugin to display paging on categories pages
4. They are not naturally aligned for all select option buttons to be inline so depending on the length of titles your page can look messy
5. the shortcode doesn't allow for pagination so you are set to the number of products you can display through a category shortcode on a page.
Product display
The shortcode for multiple products isn't working for me and it naturally aligns them on a seperate line for each product so not good for trying to add a selection to a post or page.
Checkout/conversion
User can guest checkout or create an account, you can create a wordpress user then link them to their order based on the information submitted but personally I would prefer it to create an account for the user automatically and send them the details when they order like shopp does.
Shipping options
Limited by themselves but the table rate plugin offers a great solution allowing you to create different rules for different product groups, although it is time consuming to set up it can allow you to be very specific and offer a lot of different options and priorities rules, a fabulous solution for a very complex problem.
However, with these negatives in mind, this system is still hands down the best eCommerce system I have worked with so far even though it is still in its infancy with the arrange of plugins growing every week it just keeps getting better (although it will cost you in extras plugins range from $12 to $50/75)
The problem I have found with Magento is although out of the box it is a good system, extras are expensive and it is very cumbersome to manipulate and get my teeth into. I decided to drop it entirely when I heard eBay bought it as if they run this project like their other businesses then I see trouble and much frustration for programmers ahead.
There is a new multiple product import plugin for woocommerce and some bulk management plugins as well so you may want to look into this before adding manually as they may save you a lot of time.
Hope this helps
