One main issue I see with the Emic solution is that it does not support transactions. I saw their demo at the last LinuxWorld in SF and they are just using a multicast layer to broadcast the queries to all nodes (they don't parse SQL so they can't handle transactions properly).
Moreover, if you have queries like UPDATE ... WHERE date=NOW() , you will just get a different result on every node! At least, solutions like C-JDBC replaces macros such as NOW or RAND on the fly so that all databases are consistent.