Gbuy could give Paypal a real run for their money, but it won't be easy. The great thing about all things Google is that its services are user friendly and minimalist. Paypal is, too. Google usually has a leg up with the minimalism thing, but Paypal already has that. Moreover, it has tens of millions of users that are satisfied with it.

I think Gbuy needs to look at where Paypal fails and make improvements there. Do a search on "paypal" and you immediately see sites that center around paypal horror stories, e.g. tuition money held, etc.