I'm also very curious to hear real world feedback on this, I've been aware of the option for a while, but never heard much about actual use.

Automatic sharding and memcached integration are pretty awesome features, and could definitely ease code at the application level (sharding code is a particularly special pain in the ass, not so much getting it working, but allowing for re-sharding migrations if you decide you need more shards, especially trying to do so without downtime which involves all sorts of nasty tradeoffs).

But bang-for-the-buck and reliability wise, I'm still unsure, I've heard very little about this in the wild. Is this more suited for high write v. read ratio situations, or is it aiming more at the Vertica/Greenplum big-data uses, or something else?