The overall experience with Aerospike is highly positive. In particular database response times are short enough for real time applications.

The database structure made of namespaces-sets-bins allows to store many different data for different purposes. The Spark connector is helping me linking Aerospike to our existing computation platforms.

There is no clear documentation (so far) about all the error code you can encounter while working with Aerospike

We were looking for speed and scalability, and with Aerospike we got exactly that. It's simple enough to manage, has some additional monitoring tooling. To avoid nasty surprising when buying this software - make sure you read the docs thoroughly, at least twice.

It's quite expensive. You have to use Aerospike's client libraries, which don't always offer compatibility with all the Aerospike features (mostly Ruby). Remote training sessions are very basic, you'll better off reading the documentation and asking support specific questions if anything's unclear.

Operation per second was fastest among other in memory DB

It has no transactions -- the biggest flaw of this software, unless you are using it only for memory store it works great