Clearly articles like this are designed to promote the service rather have any substantive "hacker" news. That said, the front page looks compelling except for one thing -- NO PRICING. It doesn't matter if it's still in beta. You are asking me to commit to a completely new workflow -- it's not worth my time unless I have some idea how much you are going to hit me for once it comes out of beta. $9/mo? $99/mo? I mean c'mon, give me something...
Note that flowdock was on the obsolete Cassandra 0.5; the little they described of their problems suggested that upgrading to the 0.6 series would solve the worst of them.
I have noticed a disturbing trend used in the defense of many NoSQL products --> When faced with criticism point out that there is version n+1 now available and they should have used that, it would have fixed everything, etc.
We've seen this, ironically, in reference to many MongoDB horror stories, so it's interesting that in this case it's the case where someone is moving to MongoDB.
To be fair, many of these products are in their infancy so yes in general the fix may be in version n+1. I don't think that's a defense of NoSQL products it's a common thing with any young product.
Anyone who chooses an early product would hopefully understand that they will be experiencing issues and will be upgrading the product many times as issues are found and fixed.
Cassandra has a lot more installations pushing hard on it in 0.6 than it did in 0.5, many of whom have worked with me and other committers to resolve their issues, so it's not just paint-by-numbers handwaving on my part.
Here are some of the changelog entries from 0.6.2 that are relevant to high-volume sites:
In you article, you mentioned 'Dots are not allowed in BSON document keys. Typically it might not be a problem, but we had to work around it in our data migration.'