But the term "vaporware" exists for a reason. Waiting for something that may or may not be everything it's promised is risky too. The Maglev ruby VM is a good example; they were demo-ing close to 10x performance a couple years ago, but when they finished implementing the fully ruby spec it was something like... 20% faster.
A lot can change when you go from demo-ware to a real production ready product. Neither Fathom nor Volt is going to be at Cassandra levels of stability in 3 months. More like a year... if things go well.