To speak with Cassandra do I utilize both or one or the other?
Given this advice by Dave, who rocks, I’d say neither.
http://www.davegardner.me.uk/blog/2010/07/02/php-and-cassandra/
Many in the Cassandra community recommend using a high level client (such as the two listed above):
http://www.datastax.com/docs/0.7/api/high_level_clients
I started out using raw Thrift, which I still think is a useful way of understanding the actual Cassandra API. That said, if you’re starting out now you are probably best off with phpcassa.
http://wiki.apache.org/cassandra/ClientOptions
Dave