From my limited experience I think Cassandra is a dangerous choice for
an young limited funding/experience start-up expecting to scale fast.
Its not dangerous, just do not try to be smart and follow what other big
cassandra users like twitter, netflix, facebook, etc are using. If they
are still at 1.1, then do not rush to 1.2. You can get all informations
you need from github and their maven repos. Same method can be used for
any other not mainstream software like scala and hadoop.
Also every cassandra new branch comes with extensive number of difficult
to spot bugs and it takes about 1/2 year to stabilize. Usually new
features should be avoided. Best is to stay 1 major version behind. This
is true for almost any mission critical software.
You can help with testing cassandra 2.0 beta. Create your testsuite and
run it against your target cassandra version. Test suite also needs to
track performance. From my testing performance of 2.0 is about same as
1.2 in my workload.
I had lot of problems after i migrated from really good working 0.8.x to
1.0.5. Even if preproduction testing did not discovered any problems,
there were memory leaks in 1.0.5, hint delivery was broken and there
were problem with repair making old tombstones appear causing snowball
effect. Last one was fixed about 1year later in mainstream C* after i
fixed it myself because no dev believed me that such thing can happen.
