We wholeheartedly support X-Payments. We really like that our customers can submit their CC info without having to leave our site. We are a small retailer, but the integration gives our site the smooth checkout process that customers are used to with large retail sites. Yes, the initial investment may seem high, but benefit of the image of a reliable, safe site is worth it.
I would be happy to post this message anywhere it would be helpful so that more sites use X-Payments. It's good for all of us.
Note that X-Payments works with Magento, Zen Cart and osCommerce as well as X-Cart.