Complex sentence: The only dedicated transatlantic ocean liner in operation as a liner, as of February 2010, is the "Queen Mary 2" of the Cunard fleet, however she also has the amenities of contemporary cruise ships and sees significant service on cruises.
Split into simpler sentences: The only dedicated transatlantic ocean liner in operation as a liner, as of February 2010, is the "Queen Mary 2" of the Cunard fleet. She also has the amenities of contemporary cruise ships and sees significant service on cruises.