[3amOpsGuy]

What else would you say is good about Cassandra?

I find the datamodel inflexible and often hard to work with for real world use cases. I think the tooling is immature and the hector API leaves me feeling depressed (pycassa and astyanx are quite a lot better).

All that said, I find cassandra to be fast, incredibly fast. 99th percentile on our 9Tb time series store is around 20ms on below par hardware.

Another thing i like is we've never had downtime, not even scheduled. We've had nodes fail, we've had datacentres isolated during disaster recovery tests, yet our cluster has continued on regardless (2 x sub clusters per region). Whatever way you stack it up, that's impressive. Remember with cassandra there's no load balancers or other shenanigans involved.

Garbage collection / virtual machine concerns are a red herring due to the mechanics of a cassandra query (certainly for CL < RF)

[jchrisa]

I'm glad you are happy with 20ms, to me it is slow...

Probably the best thing about Cassandra is that it is written in Java, so it is easy to fork and add custom behavior. Of course this is orthogonal to performance.