BigCommerce

I loved the versatility available for building product pages, being able to set it up so pricing adjusts automatically for different product options, and the import/export functions to update large inventories via Excel documents instead of manually editing within the web app.

Initial setup can be confusing, especially when new to e-commerce and knowing how to tell it to calculate tax, shipping, etc. Their customer service is great though, so if you're confused about a setting you can call and talk to someone very quickly. I rarely ever waited more than 5 minutes to talk to a rep.

Easy product management, plenty of payment gateways available, decent theme store. Handles product options / variants better than Shopify. Has some good B2B / wholesale features out of the box.

Themes are over bloated with way too many files. You can't edit the CSS and JS files online. Makes relatively easy changes (on other platforms) too time consuming. Often suffers from indexing delays and/ or caching issues so that your changes or new products you add take 30+ minutes to show up on the site. Main navigation menu is automated. You have to either hard code a menu or use an app if you want customizations to your menu. Stencil CLI can either work smoothly for editing themes or you'll spend hours chasing down compatibility issues. No way in store to easily find orphan pages.

Out of the box, BigCommerce has more built in features than other online carts out there. Pretty straightforward setup making it fairly easy to get up and running in little time.

Not as easy to customize themes/store interface. When you edit the source code you need to make sure you document what was done as the changes don't carry over when you update the theme of your site.