Keyboard cannot possibly beat a good HOTAS in a simulator.
Sure, it and mouse may be more precise, but I don't imagine looking for all these functions and keystrokes.
Also, precision only matters in a gunfight, on longer ranges where missiles are used, ability to manage the radar, scan, lock targets, controll the plane and ECMs simultanously gives a tremendous adventage. That's what a real HOTAS can do, for example CH Fighterstick+CH Pro Throttle, Thrustmaster HOTAS Cougar, Logitech G940 or any similar high-end HOTAS system.
On a keyboard, you can do only two of these things at the same time (at least, with default configuration) .