1) You are starting with a blank canvas
2) You will be dealing with low-level primitives
3) You have complete freedom in what you build
4) It's fast if you use it right
For each one of these items you could look at it and say "that's awesome" or "yikes." You know which group you are in!
I hope more people in the 'awesome' group realize that using FoundationDB can transform the development of a new distributed data store from a multi-year project into a few weeks of hacking. This is because FoundationDB solves the scalability, fault tolerance, and ACID parts for free--the least creative and most time-consuming aspects.