I don't think BTCPay Server will be a valid replacement for third party payment processors.
Here it is the list of my thoughts resulting from my experience with BTCPay server:

- You need to configure and deploy, maintain and monitor the server by yourself. This is not as trivial as it may sound. You need to start he wallets, connect the job to the wallet and deploy everything.

- Even pushing everything on Azure VMs, you will still incur in Microsoft to sporadically restart the VMs/Cloud services/Web apps and this would potentially generate downtime and errors during the daily payments processing.From my standpoint, this is not acceptable for a payment processor service.

- You will still need to monitor/upgrade the Wallet(s) that BTCPay is attached to manage the payment requests.

Adopting a third party payment processor, all the points enlisted above are completely covered by the payment processor itself and that is not trivial. Obviously you will probably have to pay a service fee for this which depends by the processor itself.

I think instead, that what is important to consider when you chose a Bitcoin processor is what that processor really offers in terms of functionality set, fees applied, how reliable this processor is.

In the list payment processor enlisted, there are really well known processors like Bitpay, Coingate, etc, I see a processor I didn't hear about before SetGetGo. Interesting they apply a flat fee. As far as I can tell no other processors do that. The real question would be how reliable SetGetGo is.

Does anybody actually use SetGetGo for Bitcoin payments?