[bkeroack]

CQL is the best and worst thing about Cassandra. The pro is that obviously it is very similar to SQL so it's easy to understand, the con is that C* is nothing like a RDBMS so you can be easily fooled into doing dumb/inefficient things with the nice CQL syntax.

I think that Cassandra is best thought of as a fancy K/V store that lets extra data ride along with query results. Don't think of rows/columns at first, it will just screw you up in your modeling. Also keep in mind that the cost for very fast queries is a lot of extra time spent figuring out how to model new data access patterns in the future.

[Boxxed]

I'd say it's absolutely the worst. For about ten seconds it seems like it's a nice higher level abstraction, but then you realize how that abstraction is hiding exactly what you care about: how your data maps to the underlying storage. Making it look like SQL was also a huge mistake because it gives the impression of a certain level of expressivity that it by no means has.

[jjirsa]

The clustering provides a ton of speed improvements if your data model can keep partition sizes small - especially if you use spinning disks, cassandras storage engine will make reading adjacent rows in a partition nearly free (especially with modern OS behavior like readahead).