Ignoring reserved prices, it is $10.40/hr (these are eventually consistent reads, so half the cost of consistent ones). That puts it roughly on par with an RDS postgres r3.8xlarge instance with 10k provisioned IOPS.

Sure, you likely have more than one table on RDS, so that cost is amortized, but when you get to the scale where you need 160k reads/s, you aren't going to have much more than that one dataset in a single instance.