Easy to use the site. HOwever, after input of credit card details they prompt you if you'd want an upgrade but they don't put in the additional fee that needs to be paid. They only show the amount you've paid already, letting you think that the upgrade would be free. But after you click on upgrade, that's the only time they reflect the total full amount charged to the card, which was in my case, an extra 50sgd. There should have been a confirmation first. Sigh.