I'd love to use riak for all the reasons mentioned in this article, and more.
The single missing 'feature' (design decision) that I can't live without, is that you can't efficiently do range queries/order-by on the key in riak today.
Hopefully this will get easier with secondary indexes / riak-search integration. Not clear yet.
If we are talking about performing range queries on an index then Riak already has it in the form of Riak Search. In 1.0 this is also supported by secondary indices.
If we are talking about performing a range operation on the primary key which returns the matching objects, then no, Riak doesn't currently offer that. However, given it's support for an ordered data store such as leveldb in 1.0 it should only be a matter of time before that is possible.
Just to try it out I already implemented this for fun on my fork.
The single missing 'feature' (design decision) that I can't live without, is that you can't efficiently do range queries/order-by on the key in riak today.
Hopefully this will get easier with secondary indexes / riak-search integration. Not clear yet.