SolidTrustPay remains the only IPN processor that allows Fiat as well as Crypto Payments.
Uphold is good however they have no method of callback yet but it does support all forms of payment except Card (but members can use a Card to credit their account) so if you wanted to use them you'd have to manually upgrade or credit your members should they purchase anything.
Stripe allows payment via Credit/Debit cards but their integration is pretty complex and not as straightforward as Paypal or STP. You can still use the Checkout option but again you would need to process a members payment manually. Automation is possible but tricky especially for subscription based products.
Coinpayments was good up to the point they decided to outsource their KYC (Know your customer) to a private company and on a decentralised currency that's a very odd move to make. The worst part is how they executed this KYC as I went through it 4 times and was told that I was a different person to the account which is absurd considering there were no personal details on CoinPayments to begin with so how would they know the documentation was not for the person who owned the account? I contacted their support who told me to contact the outsourced company who told me to contact Coinpayments support and at that point I removed CP as an option from my site and went with an exchangeless Bitcoin option.
Payeer is another good processor and it works very similar to Paypal except it also accepts Crypto. The reason many people are not using it though is likley because its a Russian Company and we all know how much the West (Governments and Media at least) hate the Russians lol. Personally I think its an excellent processor and in all the time I have used it, it has never had any problems. The integration works exactly the same as Payal.
ORU charges a monthly fee to use and is based in a tax haven. Enough said lol. Who knows that might be the western version of Liberty Reserve
Transferwise is an excellent processor however it again has no callback so were you to use this processor your members would have to be manually upgraded. The best part about TransferWise is it uses what is called borderless payments which means you can transfer money country to country without any charges. Also you can hold it in various denominations like USD, EUR, GBP, etc to keep track of your payment sources.
BitPay is good but it is not very developer friendly and their sandbox for testing is awful. Plus in order to buy anything using crypto your member would have to use the BitPay wallet application so not really compatible with say someone who has a different BitCoin wallet but wants to buy something on your site.
Those are the main ones I know of and of those 8 I use 3 on my sites with no issues with Bitcoin being handled on a Wallet to Wallet basis so no go-between but still automated (SolidTrustPay, Stripe, Payeer)