Disclaimer: I run a consulting company that fixes horrifying AWS bills. By and large, this is going to make life a lot easier for most of my clients. That sai

Disclaimer: I run a consulting company that fixes horrifying AWS bills. By and large, this is going to make life a lot easier for most of my clients. That said: * You still have to watch out for generational changes ("Oh, you have a lot of reservations for i2 instances? That sucks, i3s just came out, are a third cheaper, and you can't use your RIs for them."), so 1 year is still where it's at unless you're doing something like writing your cloud spend as CapEx. * You still need to figure out how your application profiles. Converting an m4 reservation to a c3 isn't happening. * Smaller instance reservations apply to larger instances, and pro-rate the difference down to on-demand pricing. This is "the right thing," but it's going to make Amazon's already byzantine billing even harder to dissect.