If you have a bog standard ecommerce store and don't need to do anything fancy or stand out of the crowd now or in the next 5 years then Shopify is a good choice for you.

If you've seen something on another ecommerce site that Shopify doesn't have and you think you may want to grow your business to use it then I would seriously look at investing in WordPress with WooCommerce now. It is not easy to move from boxed solutions like shopify to something else.