Things change rapidly in the WordPress world. The content in this post is more than a year old and may no longer represent best practices.
The main topic at the March 2014 East Bay WordPress Meetup was iThemes Exchange, the most recent e-commerce plugin. Meetup description:
iThemes created Exchange to be easy to use: an end-user’s shopping cart. Chris Lema has heralded it as the simplest shopping cart (or membership system) to set up.
This is not what you want for your complex custom jobs, but it might be what you want when clients need an easy way to sell a few products. (One of mine found it a lot easier to work with than Shopp, which she replaced with it.)
Let’s take a look at the features and extensions so far available and put them into the context of existing solutions like WooCommerce.
An examination of Exchange and its add-ins revealed one major flaw: no product variations. For anyone selling physical products (mugs, T-shirts, etc), this seems like a deal-breaker. (Product variations are in the development pipeline.)
Other aspects of Exchange are more appealing for instance: separate product entry pages for physical products, digital downloads, memberships, etc. This saves having too many options on one page. The product video field is also a nice touch.
Overall, iThemes exchange seems like a product to watch. It has ease of use in its favor.
Price-wise, it seems much of a piece with WooCommerce: the base plugin is free, but most of the interesting stuff costs money.