Shop Pay Express Checkout is a new integration for Ongoing Subscriptions.
Shop Pay increases checkout speed by 4x.
It’s an accelerated checkout (it saves all of your customer’s information for a faster checkout).
it also offers a very clever installment plan system for your customers.
"Shop Pay offers customers the option to pay in full at checkout, or to split their purchase into four equal, interest-free installment payments for orders between 50 USD and 3,000 USD. There are no additional charges, interest rates, or late fees passed on to customers." - Shopify.com
It works out of the box with Ongoing Subscriptions.
If you are using Shop Pay on your store, it will automatically work with subscription products in the cart and checkout for your customers.