As sprizzle says, F1 and Dremel are not competitors; Dremel is a read-only system supporting large analysis queries, while F1 is a read-write system designed for large numbers of smaller queries. Last year Google published a paper on PowerDrill (http://vldb.org/pvldb/vol5/p1436_alexanderhall_vldb2012.pdf), which sounds somewhat like Dremel but is designed to use large amounts of RAM, which in turn enables some very powerful optimizations.