Can eCart work where Zen Cart was requested?

I have a client who wants to take his online store "up a level," and I am hoping to finally get a chance to use eCart (and DataBridge if that's appropriate and helpful). We have upgraded his PayPal account to "PayPal Payments Pro."
My client has a fulfillment house that is shipping all his products, and they want our orders to hook up with their database. They have other websites they fulfill for, and some of those use Zen Cart for a shopping cart. Their IT guy wrote this to me when I indicated I'd like to use eCart:
"The nice thing about using ZenCart is that we have created a solution for a client that accesses a ZenCart database remotely and extracts and updates data on that database directly. Our hope is that how you implement this (as well as the version of ZenCart used) will not be too different than the solution for our previous client. This would allow for a rapid and less expensive integration.
"We are unfamiliar with eCart and its database schema. The difference in modifying our ZenCart integration to use eCart may be small or it may be large – we wouldn’t know. Consequently, I would recommend ZenCart unless there are significant advantages to using eCart."

Can I assure him eCart could work? Would there be any advantages I can claim for it? Would it be safer/wiser/easier to just use Zen Cart?

I have never done ANY shopping cart before, and I purchased a bunch of your products hoping to be able to leverage them as I try to get up to date in my web development. Of course, e-commerce is huge, and I'd rather apply my learning to a set of tools from WA than jump around from one open source app to another.

Anything you can offer by way of specifics, tutorials, etc. would be GREATLY appreciated.

Many thanks!

- Dan