If you update a Subscription product price from $100 to $120, all those Subscriptions created at $100 are not updated to $120. You have to manually go to EACH subscription and update the price which is very time consuming when you have hundreds or thousands of subscriptions. There should be a bulk way to update all subscriptions pricing without having to go one-by-one through each active subscription.
BigCommerce is most easily compared to Shopify. Both platforms offer a similar experience when building an ecommerce platform. Like Shopify, BigCommerce offers a range of prices and packages tailored to different types of businesses. The platform is highly customizable if you are comfortable with some light coding. It is also possible to use themes and templates to build your website, but some of these will come at an additional cost.