> "Accumulo's cell-level security makes it possible to set access control for individual pieces of data using 'visibility tags.'"
Are these so-called "visibility tags" really crypto-capabilities?
It sounds more like labeled security. (SENoSQL?)
I'm curious to see how things will play out between the likes of Accumulo and HBase.
Yes, it will be interesting. HBase has a larger community and user base, which will surely help in its adoption. Accumulo & HBase have very similar architectures and purposes, so much that the NSA caught a little heat from the Senate (http://www.wired.com/wiredenterprise/2012/07/nsa-accumulo-go...). If you absolutely need cell level security than you might want to go with Accumulo, otherwise, use HBase.
Does it come close to the advertised performance efficiency of BigTable? HBase is a resource hog, often blamed on the unoptimized Java of the Hadoop stack.