In general, PayPal seems to work well once you get it set up. But sometimes the smallest things interfere with that setup. It took nearly and hour and a half, and 3 PayPal support technicians to figure out why a Paypal payment page was forcing the customer to create a PayPal account, instead of allowing either a credit card payment or a PayPal account. It turns out that the PayPal account name (an email address) had been entered with the first letter capitalized, but I had been using all lower case. Also, the email address in question, had not been verified (although it had been used back and forth with PayPal).
Once those two corrections were made, the payment system worked just fine.