It seems impossible to get an decent answer from wp-e-commerce people on anything. Plus, they seem to have an attitude. Support, even when you pay for products, is virtually non-existent, a bad omen for a reasonably sophisticated product like a shopping cart.
Lacking support, I had to purchase the gold and membership to test the product.
Regular PayPal seems not to work completely in the free version according to their site, but seems to work okay when you pay for the Gold version. In their documentation there is this note: "Known issues (2008-07-21): PayPal Express Checkout doesn’t work properly." Four months without fixing something so basic is really bad.
wp-e-commerce DOES NOT support PayPal Pro. PayPal Pro is very popular in the US, but apparently not in New Zealand. They do support PayPal Payflow, a different PayPal product for which you need a merchant credit card account with a bank or other vendor.
They support a bunch of other cc gateways that customers in the US have never heard of.
If you try to use the membership module, forget it. wp-e-commerce commits the deadly sin of requiring site sign-up before people can complete a purchase. Seasoned e-commerce people know this is deadly since people just want to buy, they don't need to be side-tracked by wp-e-commerce program requirements. Requiring separate site sign-up before they input their purchase data is a major sales killer.
wp-e-commerce people blame this and other issues on PayPal, but other non-wp carts have overcome these issues.
wp-e-commerce people have a potentially great product, but it is very far from being ready for prime time. I have lost time, and money paid to them, just to see if it was as good as they say. I don't think it is.