If you want an avionics/cockpit sim, yep both Janes F/A-18 and Falcon 4 are it. Falcon 4 also has a pretty good dynamic campaign engine. Huge selection of community-made add-ons including updated game engine, additional aircraft, terrain, graphics etc etc.
If you want flight/combat simulation with hi-action sea battles and carrier landing, intense Air to Ground action, and ultrarealsitic flight simulation, Flanker 2.5 is it. Flanker 2.5 has no campaign but has a very powerful mission editor. You get to fly the Su-25/27/33/39 and the Mig 29.
PS - I own both Falcon 4 and Flanker 2.5 for both reasons.
Vruth