I think in practise though we serve a very different segment. Lago is great for high-throughput event metering and mainly target series B+ companies. They don't yet have an offering for feature permissions management (aka entitlements).
Autumn is built more for early stage companies that have payments in-app. Hence we're trying to invest more in the developer experience (eg React hooks), while also providing that abstraction layer for entitlements too.
We absolutely will be adding more payment providers soon. Our biggest requests are Polar and Razorpay for the indian market.
The main reason that people use us is permissions management. We are the source of truth for which of your users can access what, and linking that to billing. Eg, we know that because user ABC is on Pro tier and bought 3 top ups, they have access to 75 AI credits. If their next payment fails, they should only have access to 15 AI credits (etc etc). Our value is in handling this matrix of scenarios related to usage resets, billing cycles, transitioning between monthly and yearly plans, etc.
Lago only handles billing, so if you're using them, then the logic to sync up the user's permissions with the billing state has to be handled yourself.
It just turns out that most of our users are only really interested in using Stripe at the early stage, so for now our codebase is closely embedded into their billing product.
It's going to be fun(?) ripping all of it out and moving towards a PSP agnostic architecture you mentioned.
Lago is better in that they have have support for custom payment integrations [3].
[2] https://paystack.com/stripe/south-africa
[3] https://getlago.com/docs/integrations/payments/custom-paymen...