This help page lists the only payment services we currently support:
http://www.e-junkie.com/ej/help.payment.processors.htm
Of those, only PayPal Payflow Pro would be a true payment gateway, which you could use as an alternative to Authorize.Net for authorization of direct payments from the buyer's card to your choice of Internet Merchant Account (IMA), without having to also offer a PayPal account-based checkout option.
While PayPal Payments Advanced and Pro also have payment gateway functions built-in, I think those may only work with an IMA provided by PayPal, though it appears Advanced has a setting to specify a different "Partner" as your IMA provider, and both of these require offering a PayPal account-based checkout option.
With the news of Google Checkout being retired as of Nov. 20th, we are evaluating other payment services for which we might add support, so feel free to offer suggestions of any payment processors or gateways you might prefer.
