Cassandra with PlayORM/Astyanax has been the easiest database for me to install, use and manage out of the 10+ I've tried. Far simpler to install/manage than MySQL Cluster or Riak, far easier to use than PostgreSQL and infinitely better to scale than MongoDB.
You don't have to understand ColumnFamilies, consistency or the different topology strategies. The defaults are fine and if you are a Java developer life couldn't possibly be simpler.
It's not a trivial topic and unfortunately "it appears to work as you'd expect" on a small dev cluster which can lead to statements like yours.
Your parent's post is actually very very accurate.
They ALL have issues and eventual consistency is a fundamental part of a distributed database so its something you have to learn either way.
There are more details on the options here: http://www.datastax.com/docs/1.2/dml/data_consistency
This is a recipe for disaster. Cassandra requires careful understanding of its claimed consistency guarantees to be used properly. Proper use of the ConsistencyLevel argument is pretty critical if you want to build a real site that actually works under load.
Whaa?? Fine for what?
I agree with the OP. I used cassandra at a startup for a year, about a year ago, and haven't used it since last April. I'm sure things have progressed some (and we were using SuperColumns which a new user today might not) but the idea that it's a black box you don't need to understand? Not at the load we were putting it under.
But if you're a Java developer then PlayORM/Astyanax abstracts away almost all of the complexity and allow you to focus on your data model and not worry about the columns. Likewise for the preferences the defaults make sense and are pretty straightforward to change if you do need.