MonetDB: designed for super-fast in-memory execution via vector operators; tends to thrash once you go beyond what can fit in memory since the algorithms aren'

MonetDB: designed for super-fast in-memory execution via vector operators; tends to thrash once you go beyond what can fit in memory since the algorithms aren't designed for that. X100 is supposed to address that but no one has seen it yet. LucidDB: optimized for the case where your data does not fit in memory. Supports a lot of additional ETL-related stuff like upsert, Java row-level transformations, foreign data extraction, warehouse labels, hot backup. Infobright: don't really know; their community edition is intentionally limited (e.g. doesn't support DML). Slightly smoother transition if you are already a MySQL shop. Vertica: clustered, optimized for taking advantage of multi-sorted materializations, pricey (OK, the last one is non-technical). Sybase IQ: don't know.