They are shipping a closed source black box and advertising their own demos and tests for a while. Just like this one. Not sure how much I would trust that more than just having a marketing statement saying "oh yeah we are the most stable, fastest, etc".
That and the quite low limits for transaction duration (5 seconds!) make FoundationDB a no-go for me.
Closed source + very narrow limits due to system design makes this a very hard sell.
It's a pitty because they do seem to have some decent ideas in there. I like the layers that build more complex data models upon a transactional distributed key-value store.