I've written an article before on this topic:
http://aleveo.com/ideas/real-time-variable-pricing-for-the-w...Surely I think it is a good step forward, but there are two sides of the equation, maximizing profits and providing fair value for the price.
If the company wants to maximize profits they might just as well start with highest possible price as tybris suggested. However, price has always been related to scarcity, and if there is no control of the same, the offer gets commoditized , hence the real and perceived value is not appropriate. The book Experience Economy talks a lot about this.
EDIT: In any case, the one that is concerned with fair value has a sustainable advantage over the one that is looking for ripping off customers. Dynamic pricing should involve many variables, such as time since marketed, total sales, stock, discounting, revisions etc, but I would keep all of this information out of the sight of customers as it may appear very confusing and irritating for the conservative ones.
I am not sure whether they are doing it right here, but I have great respect for experimenting. Behind every great invention there is an exploded lab :D