I am not a developer/engineer so
please excuse my ignorance (and feel
free to edit where I have not
expressed myself correctly)
In particular I would like to know if Joomla is sufficiently complex to handle:
- Using the API of several logistics/delivery services
- Doing A/B testing
- Integrating seemlesly with a payment gateway
- Any other important things I am not even thinking about just yet?
You don’t really want to know about Joomla, you want to know about the e-commerce extensions for Joomla. If you are purely going to be selling products and not producing any content, then I would probably opt for a dedicated e-commerce solution like Magento. If you need the additional features for managing content outside of the products you intend to sell then I would go with Joomla + Virtuemart + k2 + K2mart. Joomla and K2 will handle all of the content needs you may have. Virtuemart is the most robust of the e-commerce packages but it can be hard to work with for product display, which is why I recommend K2mart. This allows you to use the checkout portion of VM – payment processing, shipping calculations, invoices and notification with the power of K2 templating to display product categories and detail pages. It also makes your e-commerce pages much more SEO friendly. All of those are free extensions with the exception of K2mart which is very reasonably priced.
Virtuemart has a large selection of shipping options including several popular shipping services with APIs. They have payment processing for all of the big paymeny gateways. You can do A/B testing with an extension designed to integrate with Google Webmaster Tools.