DataStax Enterprise 4.0 In-Memory option

Somehow I have managed to miss this announcement. It was back in Feb. 2014. I must admit that I strongly believe, that popularity of the product (person, movie, book - you name it ...) depends not on a quality and feature set (person has a feature set,. as well :)), but on some other factors, like money spent to promote product ( person, movie, book, etc). Cassandra and MongoDB are good examples ...
The former is still struggling to get counters done right, the latter promises not lock table for every write operation... in next release, of course.

OK, here is the link to the tech paper:

http://www.datastax.com/wp-content/uploads/2014/02/WP-DataStax-Enterprise-In-Memory.pdf

It contains everything except raw benchmark performance data, but the most anecdotal statement can be found at the end of the document:

Because in memory tables are stored on the JVM heap, the total SIZE_LIMIT_IN_MB for an in memory table should currently be limited to 1GB per node, with amount also being dependent on the heap size and the need to leave room for normal Cassandra activity.

Cassandra, you say? :)