NoSQL Storage Systems Never Violate ACID. Never? Well, Hardly Ever
danweinreb.org
danweinreb.org
Lets see, from the article noSQL solutions are ACID if each transaction updates a single record, if you have sharding and no replication and if you have fsync turned on.
The default state of SQL servers - MySQL non-innodb aside - is reliable i.e. ACID. The default state of noSQL solutions is unreliable, and only Voldermort seems to go some way to addressing that.
Is voldermort the only reliable noSQL?
Also you casually mix in "default state", so you need to decide if you're going to include all the possible modes of the more flexible stores out there or if you want this to be a silly attack on default configs.