FotoMerchant is true to it's name as it has the most ecommerce features of any builder on this list, including fulfillment through their own printing center. They also allow you to sell digital products (for an extra charge per megabye), and lost of other sales features. They are based in Australia and their customer support is above industry average.
Plans start at $12/month, going up to $99/month for digital downloads delivery and extra searching and tagging features. Plus, there's a transaction fee that starts from 15% for the lowest plan and goes down to 2.5% for the high rollers.
Is it worth it? Hundreds of their clients say so, and with the 30 days free trial you can decide for yourself.