I used to use Zen Cart for a different business and have about as much coding experience as you do. I got to the point that I was holding my breath when adding modules with their page long instructions. Especially when it involved doing something to the database. I can follow directions, but if there was some kind of conflict, troubleshooting was terrible. PHP files are easy enough to go back and replace back to the previous version, but I got really good at screwing up the database Anyway, I closed that business last year.
Also, I found Zen cart doesn't include a lot of modules in the core files that seem like they should be intuitive. Stuff like if you want to control inventory by attributes, that's an addon (at least it was in 2009 when I originally loaded zencart). Prestashop automatically does that.
Now I'm partnering with someone for a new business. So a few months ago, when it came time to create a new website, I decided I wanted to find something that was a bit easier to load and ended up here. The addons are certainly easier to load with just a click. But I found that there are some necessary addons that aren't free. Like if you plan on using Paypal Payments Pro, you have to pay to get that mod. There's a free mod for paypal standard and paypal plus. I got paypal standard to work fine, but I have yet to get paypal plus to work. It just hangs there, takes the money, but doesn't send notification back from paypal to prestashop correctly. Argh... Also, if you use mailchimp, that's an extra cost. I never had to pay for addons for the payment gateway before and was a bit surprised by that. And if you want a decent theme beyond the default, you'll probably have to pay for it.
Anyway, I do find prestashop a lot easier to work with than zen cart, and the new 1.6 back office looks really amazing.