I really doubt it :) since it's hosted by PayPal after all. They make it really ugly so you consider their overpriced solutions with API :)
I herd there are also problems when too many people check out this way, something about it being slow or unresponsive, don't know if there' any truth to that though.
One thing I would absolutely love to do is be able to set the Additional fee [AUD]: as a percentage of the total and not just a static number.