When working on a SQL Tuning issue I often kick off a SQL Tuning Advisor job on the SQL while I gather info about statistics and other things I like to check when tuning. After I get an idea of where performance might be suffering I use the SQL Tuning Advisor results for a second opion.
Unfortunately more often than not the SQL Tuning Advisor reports it can dramatically improve the performance of a SQL Statement by using a SQL Profile to force a different plan.