Is it best to use trigger on destination table versus procedure dml handler for data transformation?

Considering the extra supplemental logging for using columns to compute values, it looks like it might be best to use just a straight forward Streams replication to get tables to my destination db and then use a trigger on the tables that require a lot of transformation.  I can't find examples of anything more than a simple transformation in Streams using dml handlers.  I have tables with dates that need to be converted to proper time zones using a stored procedure.  Also, some string columns must go through parsing to populate additional fields.  Which will be the more efficient and