Shopify is wider than miva, but some people may find it harder to navigate. I would also say that shopify is cheaper, since miva recently introduced extra fees. The support is better on shopify as well.

I recommend Shopify because it's very easy to use for people who know little about setting up websites. The Help section is great in answering questions and allowing you to create a site you can be happy with. Besides, the Shopify app is very easy and simple to use and it's got all you need for putting up a cool online store.I'm pretty confident with its security features.

Shopify is a really great solution for e-Comm business. Its SEO options are vast which is really important for promoting your business and saving money on it. It's really easy to navigate and has a flexible payment options. I tried using Shopify with Demo migration from Storemigration service and saw how it works myself.