Good point: if you don't need any local storage at all, then r4s are a bit cheaper. Still, an extra $576 / year (the price difference between i3.xlarge and r4.x

Good point: if you don't need any local storage at all, then r4s are a bit cheaper. Still, an extra $576 / year (the price difference between i3.xlarge and r4.xlarge) for 950 GB of SSD really seems quite cheap, especially as that's the on-demand price.