Jeff, could you elaborate on the trade-offs? When choosing between standard and this it would be helpful to understand the pros and cons. With the current desc

Jeff, could you elaborate on the trade-offs? When choosing between standard and this it would be helpful to understand the pros and cons. With the current description (below) it's as if the difference is only in pricing. But I assume there is a technical difference as well. Also, the availability number could be explained better -- why is it different. Standard - IA offers the high durability, throughput, and low latency of Amazon S3 Standard, with a low per GB storage price and per GB retrieval fee.