As for your comments:
1. Ad-Hoc SQL in VoltDB is a current area of focus in VoltDB development. We use similar compilation and expect them to be no slower than our stored procedures in the 2012 timeframe. Starting with our release next week, we'll also support multiple SQL statements in a serialized/ACID ad-hoc transaction.
2. On a single-node (or a several replicated nodes), VoltDB doesn't really have many issues with data skews. Rebalancing a distributed system is also in development, but hasn't turned out to be much of an issue with our production customers.
3. Faster at what? Single statement non-durable transactions? That's probably true for simple SQL operations for the time being. It gets murkier once you consider VoltDB features like materialized views that avoid table-scans altogether. I am also curious how durability affects performance though.
But I'm really interested to revisit this comparison once MemSQL supports real transactions and replication/sharding. For the time being, most of the VoltDB use cases we target won't run on it.