I'd highly recommend Spree (http://spreecommerce.com/tour http://spreecommerce.com/tour). It's based around the payment processor that Shopify uses, and it supp

I'd highly recommend Spree (http://spreecommerce.com/tour http://spreecommerce.com/tour). It's based around the payment processor that Shopify uses, and it supports a lot of the more advanced Google Analytics features.