Frankly, in your circumstances, I'm not sure you would see any benefit to using E-junkie in place of your existing, custom-built site. What shortcoming of your existing ecommerce platform were you looking to overcome, and what did you see about E-junkie that seemed to address that need?
E-junkie is designed to be a very simple, basic ecommerce service to meet very simple, basic ecommerce needs. Do-it-yourselfer proprietors of modest technical inclination can easily copy and paste our cart button codes into their existing sites to get started selling a fairly limited product range online, without having to install or manage any ecommerce software or payment security provisions on their own servers. This reduces the effort and technical learning required to get started selling online, especially when using a more full-featured platform may be overkill for the merchant's needs anyway; however, this may be a moot point for you, since you already have an established site where you're selling online, so the effort of transitioning from your existing, sophisticated system to our much more limited solution may not be worthwhile for you.
We also do not provide a CMS that could generate and manage site content such as an online catalog with product pages, like you have now, nor do we provide Web site hosting or handle payment processing. With our solution, you would still be responsible for building your own site and managing your product listing pages independently of us, and you'd simply copy the Add to Cart and View Cart button codes we provide to paste into your site's product pages (or you might have custom scripting developed to help automate this somewhat). To handle your checkout payments, you would integrate us with a payment processor such as PayPal or Google Checkout, or use a payment gateway such as Authorize.Net or PayPal Payments Pro for card-based direct payments.
We are also not very well-suited to businesses such as yours that have a huge number of diverse physical products that may need to be updated frequently or en masse -- e.g., imagine needing to scroll through a dropdown menu of 5000 products to edit each one individually when needed. While we do offer a $130/mo subscription plan for up to 5000 tangible products, I don't think we have anyone actually subscribed at that level or anywhere near it, and this monthly fee would only cover your use of our service, not any Web site development or hosting costs or payment processor transaction fees, which would be independent of us.
Honestly, I don't think E-junkie would be a good fit for your business as a replacement for your current, custom-built site. Your needs would probably be best served with a full-featured ecommerce software package that gets installed on your server and manages all aspects of your online storefront and sales from end to end, similar to what you already have. Offhand, I might suggest looking into something like Magento, which seems to be one of the more popular solutions of this type, with many independent developers available for hire who are already familiar with and supporting that platform. Even so, I'm not sure such an off-the-shelf solution would be any better than the custom-built solution you already have.