We are currently using both.
Shopify store:
www.rsrmoto.de
Big Commerce store:
www.rsrmoto.com
Shopify is better, I don't get why the guy upthread thinks Big Commece support is better. It is not. Big Commece staff are slower to respond and faster to send you links to guides that don't answer your questions. Shopify guys will stay with you, and send you personal video instructions.
Also we have had problems on mobile on Big Commerce. Both themes are inhouse themes, so the finger points at Big Commerce. You might still notice the issues if you check both sites out on mobile. We also had a theme update issue with Big Commerce. I think they sent us an email telling us how much better the theme will work after the update. The email did noy say it would delete all the custom work you did. And we are not web tecchies, like the guy with the clangers avatar, always telling everyone to go Woocommerce. If you are busy answering enquiries, packing boxes, ordering stock and supplies, managing channel listings, avoiding nasty feedback, managing returns, doing accounts, driving to the courier, checking stock in, cleaning the warehouse, etc, the last thing you want to have on your plate is web development. Both Big Commerce and Shopify are easy to use, the same in that context. Woocommerce is not. Either you need to roll your sleeves up and learn it or you will be paying consultants all the time for structural or design changes. Certainly there are limitations to both Big Commerce and Shopify. But you will get nice functioning website on either of them much faster than if you go Woocommerce but don't know how to use it. We would nee dot be turning over double, maybe 1.5 million to consider Woocommerce, because I would not do it without a staff member that was responsible for managing it. And I cant afford that extra staff member when Shopify only costs about 100 a month and I can manage it myself.
One big thing about Shopify, if your country cannot use Shopify payments, like ours could not in Germany until last year, then they are going to take 1% of your sale if you use outside payment providers. Not sure what the situation is now worldwide. But now we use Shopify Payments, which works well