I'm running into issue after issue with 3dcart…some minor, some not. The most recent is their "store upgrade" that now hides the area where credit card information is during checkout. You must now click the words in the checkout area. Not intuitive. Some reports are either inaccurate or incomplete and running a business with reports is annoying to say the least.
So I've looked into switching from 3DCart to Shopify a couple times and every time I'm almost in until I start to think of the nightmare of switching (more related to SEO and other customizations I have built with the current site). I'm smart enough to know what a 401 redirect is and how to move most of the site over, but it's the technical aspects of setting that up that keep tripping me up. That and the cost difference, but I know I'm gaining more functionality and integrations. Just don't want to lose 50% of business due to SEO changes etc. In the past, ~2014 I had briefly switched away to BigCommerce and immediately regretted it within 3 months.