I haven't been able to find any references to GroupedFlexible outside of FarmCode's site (purely a reference to RC2's release and the changes involved).  Has anyone used it successfully?  What's the advantage over a GroupedAnd/GroupedOr?  

Also, everytime I try to use a GroupedFlexible I get an Index Out of Range Exception.  Is this because you have to pass in a BooleanOperation for every Field that you're searching? i.e. You pass in 5 fields and thusly you need 5 instances of BooleanOperation (so field one is BooleanOperation.And, field two is BooleanOperation.Or, etc etc).