cheapflightsfares vs expedia for budget flights?

Right now I am trying to plan a trip from Miami to Frankfurt, Germany for December and I’m determined to get the absolute best deal so I’m doing a lot of comparing between the airlines, OTAs, etc.. I’m seeing what looks like the same nonstop Lufthansa flight for almost $250 less on cheapflightsfares than it is on expedia. The deal lover in me wants to book it but is the deal worth using someone other than a big name company like expedia?