It's clear they just copied (with permission? consent?) the public interface of Stripe. They tried to copy the documentation format (layout, style, presentation) too, but it came off kinda poorly (margins, people. margins). They have public test cards/accounts, but they fail to test correctly because they get "used" and can't have multiple actions performed against them. Then, there's the whole ID thing. Why the fuzzy heck would you use ugly, long, probably-going-to-run-off-my-screen URIs as IDs instead of short IDs? They advise you to never construct your own API endpoint URIs from shorter IDs, except that's exactly what they do all throughout their documentation.
But, Balanced lets you pay out next day and Stripe holds your funds for 7 days before allowing payment. So, Balanced wins on time-to-pay speed (and they have same-day transfers to Wells Fargo). Though, with Stripe I assume you could eventually have enough of a float in your account to pay out next-day under your own prior funds.
From my complete outsider point of view it feels like Balanced is full of slightly subpar copy ninjas. (obviously just on their API, documentation, and front-end presentation. Their backend could be amazing or it could be meter high jenga code.)
Disclaimer/Validator: I've written a tiny unofficial client for each each product/company. https://github.com/mattsta/stripe-erlang and https://github.com/mattsta/balanced-erlang