I just want to share this, I've been a developer for a company using opencart and working with SEO is a struggle. In opencart SEO friendly URLs are not enabled by default. In order for you to have a proper SEO you need to install an extension and that doesn't make any sense. A good ecommerce platform should have a good enough defaults. If you are just starting I would advice you to use Prestashop.
Prestashop default features that doesn't exist with other ecommerce platforms
1. Multi language
2. Modules auto update
3. Product monitoring
4. Suppliers
5. Sitemap
6. Facebook & google integration
7. One click upgrade
Prestashop default features that doesn't exist with other ecommerce platforms
1. Multi language
2. Modules auto update
3. Product monitoring
4. Suppliers
5. Sitemap
6. Facebook & google integration
7. One click upgrade