Due to our workflow, we'd benefit from showing the Guest user form (the one where you have to fill in the credit card, address, name, etc) as the first step, and then let the user log in with Paypal, but only as a secondary action.
The absolute standard is the other way around (show the Paypal login and offer to continue without logging in). One of my colleagues said he has paid like that in other stores, but I guess it's already "something of the past".
Is there a way to reverse the steps and show the guest form first?
I contacted the Paypal Tech support and they pointed me to the right place. You have to add the parameter:
LANDINGPAGE=BILLING
To your calls. They also told me to add SOLUTIONTYPE=Sole, but it didn't make a change in my case.