It's really a trivial cost compared to the DynamoDB price before. It used to cost about $3600/month to get 5000 writes/sec. Now in a bit more than 2 months you'

It's really a trivial cost compared to the DynamoDB price before. It used to cost about $3600/month to get 5000 writes/sec. Now in a bit more than 2 months you'll have broken even on the reserved price compared to the old DynamoDB price, and in a bit more than 3 months compared to the new DynamoDB price, for the 1 year investment. Any company using Dynamo for anything serious will probably rush to get the reserved capacity, since they've probably been spending a multiple of the reserved cost per month anyway.