For me - the only it does not have that I had believed it capable of, is the ability to create a static page that could sit outside of X-Cart (and its directories) that would dynamically display store products (example
http://www.vacsew.com/miele/parts/index.html). I would love to drop in groups of products onto this page, and not have to do it manually (changing prices, etc).
They have indicated that this is something they are willing to code up for me, albeit at additional expense.